Northrop Grumman Bat UAV in flight in June 2014

An unmanned aerial vehicle (UAV), commonly known as a drone, is an

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...

without any human

pilot An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Some other aircrew members, such as navigators or flight engineers, are also considered aviators, because they a ...

, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller and a system of communications with the UAV. The flight of UAVs may operate under remote control by a human operator, as remotely-piloted aircraft (RPA), or with various degrees of

autonomy In developmental psychology and moral, political, and bioethical philosophy, autonomy, from , ''autonomos'', from αὐτο- ''auto-'' "self" and νόμος ''nomos'', "law", hence when combined understood to mean "one who gives oneself one's ...

, such as

autopilot An autopilot is a system used to control the path of an aircraft, marine craft or spacecraft without requiring constant manual control by a human operator. Autopilots do not replace human operators. Instead, the autopilot assists the operator' ...

assistance, up to fully autonomous aircraft that have no provision for human intervention. UAVs were originally developed through the twentieth century for military missions too "dull, dirty or dangerous" for humans, and by the twenty-first, they had become essential assets to most militaries. As control technologies improved and costs fell, their use expanded to many non-military applications.Hu, J.; Bhowmick, P.; Jang, I.; Arvin, F.; Lanzon, A.,
A Decentralized Cluster Formation Containment Framework for Multirobot Systems
IEEE Transactions on Robotics, 2021. These include forest fire monitoring,Hu, J.; Niu, H.; Carrasco, J.; Lennox, B.; Arvin, F.,
Fault-tolerant cooperative navigation of networked UAV swarms for forest fire monitoring
Aerospace Science and Technology, 2022.

aerial photography Aerial photography (or airborne imagery) is the taking of photographs from an aircraft or other airborne platforms. When taking motion pictures, it is also known as aerial videography. Platforms for aerial photography include fixed-wing aircra ...

, product deliveries,

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

, policing and surveillance, infrastructure inspections, entertainment, science, smuggling, and

drone racing First Person View, or FPV, drone racing, is a sport where participants control " drones" (typically small radio-controlled aircraft or quadcopters), equipped with cameras while wearing head-mounted displays showing the live stream camera fee ...

Terminology

Many terms are used for aircraft which fly without any persons on board: The term drone has been used from the early days of aviation, being applied to remotely-flown target

used for practice firing of a battleship's guns, such as the 1920s

Fairey Queen The Fairey Aviation Company Fairey III was a family of British reconnaissance biplanes that enjoyed a very long production and service history in both landplane and seaplane variants. First flying on 14 September 1917, examples were still in us ...

and 1930s

de Havilland Queen Bee The de Havilland DH.82 Tiger Moth is a 1930s British biplane designed by Geoffrey de Havilland and built by the de Havilland Aircraft Company. It was operated by the Royal Air Force (RAF) and other operators as a primary trainer aircraft. ...

. Later examples included the

Airspeed Queen Wasp The Airspeed AS.30 Queen Wasp was a British pilotless target aircraft built by Airspeed Limited at Portsmouth during the Second World War. Although intended for both Royal Air Force and Royal Navy use, the aircraft never went into series pro ...

and Miles Queen Martinet, before ultimate replacement by the

GAF Jindivik The GAF Jindivik is a radio-controlled target drone produced by the Australian Government Aircraft Factories (GAF). The name is from an Aboriginal Australian word meaning "the hunted one". Two manually-controlled prototypes, were built as the GAF ...

. The term remains in common use. In addition to the software, autonomous drones also employ a host of advanced technologies that allow them to carry out their missions without human intervention, such as cloud computing, computer vision, artificial intelligence, machine learning, deep learning, and thermal sensors. For recreational uses, an

drone (as opposed to a UAV) is an aircraft that has first-person video, autonomous capabilities, or both. An unmanned aerial vehicle (UAV) is defined as a "powered, aerial vehicle that does not carry a human operator, uses

aerodynamic force In fluid mechanics, an aerodynamic force is a force exerted on a body by the air (or other gas) in which the body is immersed, and is due to the relative motion between the body and the gas. Force There are two causes of aerodynamic force: ...

s to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or nonlethal payload". UAV is a term that is commonly applied to military use cases. However

missile In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket i ...

s with warheads are not considered UAVs because the vehicle itself is a munition. Also, the relation of UAVs to remote controlled model aircraft is unclear, UAVs may or may not include remote-controlled model aircraft. Some jurisdictions base their definition on size or weight; however, the US FAA defines any uncrewed flying craft as a UAV regardless of size. The term ''unmanned aircraft system'' (UAS) was adopted by the

United States Department of Defense The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national secu ...

(DoD) and the United States

Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...

(FAA) in 2005 according to their Unmanned Aircraft System Roadmap 2005–2030. The

International Civil Aviation Organization The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international sc ...

(ICAO) and the British Civil Aviation Authority adopted 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. "Unoccupied" and "uninhabited" are occasionally used as alternatives to "unmanned". Under new regulations which came into effect 1 June 2019, the term RPAS (Remotely Piloted Aircraft System) has been adopted by the Canadian Government to mean "a set of configurable elements consisting of a remotely piloted aircraft, its control station, the command and control links and any other system elements required during flight operation".

Classification types

UAVs may be classified like any other

, according to design configuration such as weight or engine type, maximum flight altitude, degree of operational autonomy, operational role, etc. According to the

, UAVs are classified into five categories below: Other classifications of UAVs include:

Range and endurance

There are usually five categories when UAVs are classified by range and endurance:

Size

There are usually four categories when UAVs are classified by size, with at least one of the dimensions (length or wingspan) meet the following respective limits:

Weight

Based on their weight, drones can be classified into 5 categories— ."Nano, micro, small: The different drone types in India & if Jammu-like strike can be averted"
''

ThePrint The Print is an Indian online newspaper, owned by Printline Media Pvt Ltd. It was launched by journalist Shekhar Gupta in August 2017. History Printline Media Pvt. Ltd, founded by journalist Shekhar Gupta, was incorporated in New Delhi, Ind ...

'', 29 June 2021.

Degree of autonomy

Drones could also be classified based on the degree of autonomy in their flight operations. ICAO classifies uncrewed aircraft as either remotely piloted aircraft or fully autonomous. Some UAVs offer intermediate degrees of autonomy. For example, a vehicle may be remotely piloted in most contexts but have an autonomous return-to-base operation. Some aircraft types may optionally fly manned or as UAVs, which may include manned aircraft transformed into uncrewed or Optionally Piloted UAVs (OPVs).

Altitude

Based on the altitude, the following UAV classifications have been used at industry events such as

ParcAberporth ParcAberporth is a technology park created on what was Royal Air Force (RAF) station Aberporth, near the village of that name in the county of Ceredigion, Wales. The station was one of two local sites that had been used as a site for a missile ...

Unmanned Systems forum: * Hand-held altitude, about 2 km range * Close altitude, up to 10 km range * NATO type altitude, up to 50 km range * Tactical altitude, about 160 km range * MALE (medium altitude, long endurance) up to and range over 200 km * HALE (high altitude, long endurance) over and indefinite range * Hypersonic high-speed, supersonic (Mach 1–5) or hypersonic (Mach 5+) or suborbital altitude, range over 200 km * Orbital low Earth orbit (Mach 25+) * CIS Lunar Earth-Moon transfer * Computer Assisted Carrier Guidance System (CACGS) for UAVs

Composite criteria

An example of classification based on the composite criteria is U.S. Military's

unmanned aerial systems An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controlle ...

(UAS) classification of UAVs based on weight, maximum altitude and speed of the UAV component.

History

Early drones

The earliest recorded use of an unmanned aerial vehicle for warfighting occurred in July 1849, with a

balloon carrier A balloon carrier or balloon tender was a ship equipped with a balloon, usually tied to the ship by a rope or cable, and usually used for observation. During the second half of the 19th century and the early 20th century, these ships were built t ...

(the precursor to the

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

) in the first offensive use of air power in

naval aviation Naval aviation is the application of military air power by navies, whether from warships that embark aircraft, or land bases. Naval aviation is typically projected to a position nearer the target by way of an aircraft carrier. Carrier-based a ...

. Naval Aviation in the First World War: Its Impact and Influence
R. D. Layman, page 56 Austrian forces besieging Venice attempted to launch some 200

incendiary balloon An incendiary balloon (or balloon bomb) is a balloon inflated with a lighter-than-air gas such as hot air, hydrogen, or helium, that has a bomb, incendiary device, or Molotov cocktail attached. The balloon is carried by the prevailing winds to ...

s at the besieged city. The balloons were launched mainly from land; however, some were also launched from the Austrian ship . At least one bomb fell in the city; however, due to the wind changing after launch, most of the balloons missed their target, and some drifted back over Austrian lines and the launching ship ''Vulcano''. The Spanish engineer

Leonardo Torres y Quevedo Leonardo Torres y Quevedo (; 28 December 1852 – 18 December 1936) was a Spanish civil engineer and mathematician of the late nineteenth and early twentieth centuries. Torres was a pioneer in the development of the radio control and automated ...

introduced a radio-based control-system called the "''Telekino''" at the

Paris Academy of Science The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at th ...

in 1903 with the intention of testing an

airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...

of his own design without risking human lives. Significant development of drones started in the 1900s, and originally focused on providing practice targets for training

military personnel Military personnel are members of the state's armed forces. Their roles, pay, and obligations differ according to their military branch (army, navy, marines, air force, space force, and coast guard), rank (officer, non-commissioned officer, or ...

. The earliest attempt at a powered UAV was A. M. Low's "Aerial Target" in 1916.Taylor, John W. R.. ''Jane's Pocket Book of Remotely Piloted Vehicles''. Low confirmed that Geoffrey de Havilland's monoplane was the one that flew under control on 21 March 1917 using his radio system. Following this successful demonstration in the spring of 1917 Low was transferred to develop aircraft controlled fast motor launches D.C.B.s with the Royal Navy in 1918 intended to attack shipping and port installations and he also assisted Wing Commander Brock in preparations for the

Zeebrugge Raid The Zeebrugge Raid ( nl, Aanval op de haven van Zeebrugge; ) on 23 April 1918, was an attempt by the Royal Navy to block the Belgian port of Bruges-Zeebrugge. The British intended to sink obsolete ships in the canal entrance, to prevent Germ ...

. Other British unmanned developments followed, leading to the fleet of over 400 de Havilland 82 Queen Bee aerial targets that went into service in 1935.

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''

These developments also inspired the construction of the

Kettering Bug The Kettering Bug was an experimental unmanned aerial torpedo, a forerunner of present-day cruise missiles. It was capable of striking ground targets up to from its launch point, while traveling at speeds of . The Bug's costly design and operat ...

Charles Kettering Charles Franklin Kettering (August 29, 1876 – November 25, 1958) sometimes known as Charles Fredrick Kettering was an American inventor, engineer, businessman, and the holder of 186 patents. For the list of patents issued to Kettering, see, Le ...

from

Dayton, Ohio Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater Day ...

and the

Hewitt-Sperry Automatic Airplane The Hewitt-Sperry Automatic Airplane was a project undertaken during World War I to develop a flying bomb, or pilotless aircraft capable of carrying explosives to its target. It is considered by some to be a precursor of the cruise missile. Co ...

– initially meant as an uncrewed plane that would carry an explosive payload to a predetermined target. Development continued during World War I, when the

Dayton-Wright Airplane Company The Dayton-Wright Company was formed in 1917, on the declaration of war between the United States and Germany, by a group of Ohio investors that included Charles F. Kettering and Edward A. Deeds of Dayton Engineering Laboratories Company ( DELCO) ...

invented a pilotless aerial torpedo that would explode at a preset time. The film star and

model-airplane A model aircraft is a small unmanned aircraft. Many are replicas of real aircraft. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed static, display, or shelf models. Aircraft manufactur ...

enthusiast Reginald Denny developed the first scaled remote piloted vehicle in 1935. Soviet researchers experimented with controlling

Tupolev TB-1 The Tupolev TB-1 (development name ANT-4) was a Soviet bomber aircraft, an angular monoplane that served as the backbone of the Soviet bomber force for many years, and was the first large all-metal aircraft built in the Soviet Union. Design and ...

bombers remotely in the late 1930s.

World War II

In 1940 Denny started the

Radioplane Company The Radioplane Company was an American aviation company that produced drone aircraft primarily for use as gunnery targets. During World War II, they produced over 9,400 of their Radioplane OQ-3 model, a propeller-powered monoplane, making it the ...

and more models emerged during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

used both to train antiaircraft gunners and to fly attack-missions.

Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...

produced and used various UAV aircraft during the war, like the

Argus As 292 The Argus As 292 was originally developed in 1939 as a small, remote-controlled unmanned anti-aircraft target drone. A short-range reconnaissance version was also developed. The success of the project led to the Argus Fernfeuer UAV proposal. Dev ...

and the

V-1 flying bomb The V-1 flying bomb (german: Vergeltungswaffe 1 "Vengeance Weapon 1") was an early cruise missile. Its official Ministry of Aviation (Nazi Germany), Reich Aviation Ministry () designation was Fi 103. It was also known to the Allies as the buz ...

with a

jet engine A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term ...

Postwar period

After World War II development continued in vehicles such as the American

JB-4 The JB-4, also known as MX-607, was an early American air-to-surface missile developed by the United States Army Air Forces during World War II. Using television/radio-command guidance, the JB-4 reached the flight-testing stage before being can ...

(using television/radio-command guidance), the Australian

and

Teledyne Ryan The Ryan Aeronautical Company was founded by T. Claude Ryan in San Diego, California, in 1934. It became part of Teledyne in 1969, and of Northrop Grumman when the latter company purchased Ryan in 1999. Ryan built several historically and tec ...

Firebee I of 1951, while companies like

Beechcraft Beechcraft is an American brand of civil aviation and military aircraft owned by Textron Aviation since 2014, headquartered in Wichita, Kansas. Originally, it was a brand of Beech Aircraft Corporation, an American manufacturer of general avi ...

offered their Model 1001 for the

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...

in 1955. Nevertheless, they were little more than remote-controlled airplanes until the

Vietnam War The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...

. In 1959 the

U.S. Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sign ...

, concerned about losing pilots over hostile territory, began planning for the use of uncrewed aircraft. Planning intensified after the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

shot down a U-2 in 1960. Within days, a highly- classified UAV program started under the code name of "Red Wagon". The August 1964 clash in the Tonkin Gulf between naval units of the U.S. and the

North Vietnamese Navy The Vietnam People's Navy (VPN; vi, Hải quân nhân dân Việt Nam), or the Naval Service (), also known as the Vietnamese People's Navy or simply Vietnam/Vietnamese Navy (), is the naval branch of the Vietnam People's Army and is responsi ...

initiated America's highly-classified UAVs (

Ryan Model 147 The Ryan Model 147 Lightning Bug is a jet-powered drone, or unmanned aerial vehicle, produced and developed by Ryan Aeronautical from the earlier Ryan Firebee target drone series. Beginning in 1962, the Model 147 was introduced as a reconnais ...

Ryan AQM-91 Firefly The Ryan AQM-91 Firefly was a developmental drone developed during the Vietnam War to perform long-range reconnaissance, especially into China. Development The Ryan Model 147 Lightning Bug reconnaissance drone was enjoying success in Vietnam ...

, Lockheed D-21) into their first combat missions of the

. When the Chinese government showed photographs of downed U.S. UAVs via ''Wide World Photos'', the official U.S. response was "no comment". During the

War of Attrition The War of Attrition ( ar, حرب الاستنزاف, Ḥarb al-Istinzāf; he, מלחמת ההתשה, Milhemet haHatashah) involved fighting between Israel and Egypt, Jordan, the Palestine Liberation Organisation (PLO) and their allies from ...

(1967–1970) in the Middle East, Israeli intelligence tested the first tactical UAVs installed with

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmisher ...

cameras, which successfully returned photos from across the Suez Canal. This was the first time that tactical UAVs that could be launched and landed on any short runway (unlike the heavier jet-based UAVs) were developed and tested in battle. In the 1973

Yom Kippur War The Yom Kippur War, also known as the Ramadan War, the October War, the 1973 Arab–Israeli War, or the Fourth Arab–Israeli War, was an armed conflict fought from October 6 to 25, 1973 between Israel and a coalition of Arab states led by Egy ...

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

used UAVs as decoys to spur opposing forces into wasting expensive anti-aircraft missiles. After the 1973 Yom Kippur war, a few key people from the team that developed this early UAV joined a small startup company that aimed to develop UAVs into a commercial product, eventually purchased by Tadiran and leading to the development of the first Israeli UAV. 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 war at a cost of about 554 UAVs lost to all causes. In the words of USAF

General A general officer is an Officer (armed forces), officer of highest military ranks, high rank in the army, armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers t ...

George 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 Strategic Air Command (SAC) was both a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile ...

, 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

, Soviet-supplied

surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...

-batteries in

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

and

Syria Syria ( ar, سُورِيَا or سُورِيَة, translit=Sūriyā), officially the Syrian Arab Republic ( ar, الجمهورية العربية السورية, al-Jumhūrīyah al-ʻArabīyah as-Sūrīyah), is a Western Asian country loc ...

caused heavy damage to Israeli

fighter jet Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

s. As a result, Israel developed the IAI Scout as the first UAV with real-time surveillance. The images and radar decoys provided by these UAVs helped Israel to completely neutralize the Syrian

air defense Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based, ...

s at the start of the

1982 Lebanon War The 1982 Lebanon War, dubbed Operation Peace for Galilee ( he, מבצע שלום הגליל, or מבצע של"ג ''Mivtsa Shlom HaGalil'' or ''Mivtsa Sheleg'') by the Israeli government, later known in Israel as the Lebanon War or the First L ...

, resulting in no pilots downed. In Israel in 1987, UAVs were first used as proof-of-concept of super-agility, post-stall controlled flight in combat-flight simulations that involved tailless, stealth-technology-based, three-dimensional thrust vectoring flight-control, and jet-steering.

Modern UAVs

With the maturing and miniaturization of applicable technologies in the 1980s and 1990s, interest in UAVs grew within the higher echelons of the U.S. military. In the 1990s, the U.S. DoD gave a contract to

AAI Corporation AAI Corporation is an aerospace and defense development and manufacturing firm, located in Hunt Valley, Maryland, US. Formerly a wholly owned subsidiary of United Industrial Corporation, AAI was acquired by Textron in 2007. It currently operate ...

along with Israeli company Malat. The U.S. Navy bought the AAI Pioneer UAV that AAI and Malat developed jointly. Many of these UAVs saw service in the 1991 Gulf War. UAVs demonstrated the possibility of cheaper, more capable fighting-machines, deployable without risk to aircrews. Initial generations primarily involved

surveillance aircraft A surveillance aircraft is an aircraft used for surveillance. They are operated by military forces and other government agencies in roles such as intelligence gathering, battlefield surveillance, airspace surveillance, reconnaissance, observa ...

, but some carried armaments, such as the General Atomics MQ-1 Predator, that launched AGM-114 Hellfire

air-to-ground missile An air-to-surface missile (ASM) or air-to-ground missile (AGM) is a missile designed to be launched from military aircraft at targets on land or sea. There are also unpowered guided glide bombs not considered missiles. The two most common p ...

CAPECON The CAPECON project (civil UAV applications and economic effectivity of potential configuration solutions) was a European Union initiative to develop UAV, UAVs. The project ran from 1 May 2002 to 31 December 2005. The total cost was 5 136 539 e ...

, a

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

project A project is any undertaking, carried out individually or collaboratively and possibly involving research or design, that is carefully planned to achieve a particular goal. An alternative view sees a project managerially as a sequence of even ...

to develop UAVs, ran from 1 May 2002 to 31 December 2005. the

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...

(USAF) employed 7,494 UAVs almost one in three USAF aircraft. The

Central Intelligence Agency The Central Intelligence Agency (CIA ), known informally as the Agency and historically as the Company, is a civilian foreign intelligence service of the federal government of the United States, officially tasked with gathering, processing, ...

also operated UAVs. By 2013 at least 50 countries used UAVs. China, Iran, Israel, Pakistan, Turkey, and others designed and built their own varieties. The use of drones has continued to increase.Sayler (2015) Due to their wide proliferation, no comprehensive list of UAV systems exists.Singer, Peter W
"A Revolution Once More: Unmanned Systems and the Middle East"

The Brookings Institution
November 2009.Franke, Ulrike Esther The global diffusion of unmanned aerial vehicles (UAVs) or 'drones'" in Mike Aaronson (ed) Precision Strike Warfare and International Intervention, Routledge 2015. The development of smart technologies and improved electrical-power systems led to a parallel increase in the use of drones for consumer and general aviation activities. As of 2021,

quadcopter A quadcopter or quadrotor is a type of helicopter with four Helicopter rotor, rotors. Although quadrotor helicopters and convertiplanes have long been flown experimentally, the configuration remained a curiosity until the arrival of the moder ...

drones exemplify the widespread popularity of hobby

radio-controlled aircraft A radio-controlled aircraft (often called RC aircraft or RC plane) is a small flying machine that is controlled remotely by an operator on the ground using a hand-held radio transmitter. The transmitter continuously communicates with a receiver ( ...

and toys, however the use of UAVs in commercial and general aviation is limited by a lack of autonomy and by new regulatory environments which require line-of-sight contact with the pilot. In 2020 a Kargu 2 drone hunted down and attacked a human target in

Libya Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to Egypt–Libya bo ...

, according to a report from the

UN Security Council The United Nations Security Council (UNSC) is one of the Organs of the United Nations, six principal organs of the United Nations (UN) and is charged with ensuring international security, international peace and security, recommending the admi ...

's Panel of Experts on Libya, published in March 2021. This may have been the first time an autonomous killer-robot armed with lethal weaponry attacked human beings. Superior drone technology, specifically the Bayraktar TB2, played a role in Azerbaijan's successes in the

2020 Nagorno-Karabakh war The Second Nagorno-Karabakh War was an armed conflict in 2020 that took place in the disputed region of Nagorno-Karabakh and Armenian-occupied territories surrounding Nagorno-Karabakh, the surrounding territories. It was a major escalation of ...

against Armenia. Dragonfly-landing

UAVs are also used in

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

missions. The Dragonfly spacecraft is being developed, and is aiming to reach and examine

Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...

's moon Titan. Its primary goal is to roam around the surface, expanding the amount of area to be researched previously seen by Landers. As a UAV, Dragonfly allows examination of potentially diverse types of soil. The drone is set to launch in 2027, and is estimated to take a seven more years to reach the Saturnian system.

Design

Crewed and uncrewed aircraft of the same type generally have recognizably similar physical components. The main exceptions are the

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

and

environmental control system In aeronautics, an environmental control system (ECS) of an aircraft is an essential component which provides air supply, thermal control and cabin pressurization for the crew and passengers. Additional functions include the cooling of avionic ...

life support system A life-support system is the combination of equipment that allows survival in an environment or situation that would not support that life in its absence. It is generally applied to systems supporting human life in situations where the outsid ...

s. 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 crewed counterparts with comparable armaments. Small civilian UAVs have no

life-critical system A safety-critical system (SCS) or life-critical system is a system whose failure or malfunction may result in one (or more) of the following outcomes: * death or serious injury to people * loss or severe damage to equipment/property * environme ...

s, 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

design has become popular, though this layout is rarely used for crewed aircraft. Miniaturization means that less-powerful propulsion technologies can be used that are not feasible for crewed aircraft, such as small electric motors and batteries. Control systems for UAVs are often different than crewed 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 An autopilot is a system used to control the path of an aircraft, marine craft or spacecraft without requiring constant manual control by a human operator. Autopilots do not replace human operators. Instead, the autopilot assists the operator' ...

software is used on both crewed and uncrewed aircraft, with varying feature sets.

Aircraft configuration

The primary difference from manned aeroplanes is the lack of need for a cockpit area and its windows. However some types are adapted from piloted examples, or are designed for optional piloted or unmanned operational modes.

Air safety Aviation safety is the study and practice of managing risks in aviation. This includes preventing aviation accidents and incidents through research, educating air travel personnel, passengers and the general public, as well as the design of airc ...

is also less of a critical requirement for unmanned aircraft, allowing the designer greater freedom to experiment. These two factors have led to a great variety of airframe and engine configurations in UAVs. For conventional flight the flying wing and

blended wing body A blended wing body (BWB), also known as blended body or hybrid wing body (HWB), is a fixed-wing aircraft having no clear dividing line between the wings and the main body of the craft. The aircraft has distinct wing and body structures, which ar ...

offer light weight combined with low drag and stealth, and are popular configurations. Larger types which carry a variable payload are more likely to feature a distinct

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

with a tail for stability, control and trim, although the

wing configuration The wing configuration of a fixed-wing aircraft (including both glider (aircraft), gliders and powered aeroplanes) is its arrangement of lifting and related surfaces. Aircraft designs are often classified by their wing configuration. For examp ...

s in use vary widely. For vertical flight, the tailless

requires a relatively simple control system and is common for smaller UAVs. However the mechanism does not scale well to larger aircraft, which tend to use a conventional single rotor with collective and cyclic pitch control, along with a stabilising tail rotor.

Propulsion

Traditional

internal combustion An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...

and

s remain in use for drones requiring long range. However for shorter-range missions electric power has almost entirely taken over. The distance record for a UAV (built from balsa wood and mylar skin) across the North Atlantic Ocean is held by a gasoline model airplane or UAV. Manard Hill "in 2003 when one of his creations flew 1,882 miles across the Atlantic Ocean on less than a gallon of fuel" holds this record. Besides the traditional piston engine, the

Wankel rotary engine The Wankel engine (, ) is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion. It was invented by German engineer Felix Wankel, and designed by German engineer Hanns-Dieter Paschke. ...

is used by some drones. This type offers high power output for lower weight, with quieter and more vibration-free running. Claims have also been made for improved reliability and greater range. Small drones mostly use lithium-polymer batteries (Li-Po), while some larger vehicles have adopted the a

hydrogen fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...

. The energy density of modern Li-Po batteries is far less than gasoline or hydrogen. However electric motors are cheaper, lighter and quieter. Complex multi-engine, multi-propeller installations are under development with the goal of improving aerodynamic and propulsive efficiency. For such complex power installations, Battery elimination circuitry (BEC) may be used to centralize power distribution and minimize heating, under the control of a

microcontroller unit A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs ( processor cores) along with memory and programmabl ...

(MCU).

Ornithopters – wing propulsion

Flapping-wing

ornithopter An ornithopter (from Greek ''ornis, ornith-'' "bird" and ''pteron'' "wing") is an aircraft that flies by flapping its wings. Designers sought to imitate the flapping-wing flight of birds, bats, and insects. Though machines may differ in form, ...

s, imitating birds or insects, have been flown as microUAVs. Their inherent stealth recommends them for spy missions. Sub-1g microUAVs inspired by flies, albeit using a power tether, have been able to "land" on vertical surfaces. Other projects mimic the flight of beetles and other insects.

Computer control systems

AbuseMark AfroFlight Naze 32 Flight Controller rev5 white

UAV computing capability followed the advances of computing technology, beginning with analog controls and evolving into microcontrollers, then

system-on-a-chip A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory ...

(SOC) and single-board computers (SBC). System hardware for small UAVs is often called the flight controller (FC), flight controller board (FCB) or autopilot. Common UAV-systems control hardware typically incorporate a primary microprocessor, a secondary or failsafe processor, and sensors such as accelerometers, gyroscopes, magnetometers, and barometers into a single module.

Architecture

Sensors

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) refers 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.

Actuators

UAV actuators include digital electronic speed controllers (which control the

RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...

of the motors) linked to motors/

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

s and

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

servomotor A servomotor (or servo motor) is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also r ...

s (for planes and helicopters mostly), weapons, payload actuators, LEDs and speakers.

Software

UAV software is called the flight stack or autopilot. The purpose of the flight stack is to obtain data from sensors, control motors to ensure UAV stability, and facilitate ground control and mission planning communication. UAVs are

real-time Real-time or real time describes various operations in computing or other processes that must guarantee response times within a specified time (deadline), usually a relatively short time. A real-time process is generally one that happens in defined ...

systems that require rapid response to changing sensor data. As a result, UAVs rely on single-board computers for their computational needs. Examples of such single-board computers include

Raspberry Pi Raspberry Pi () is a series of small single-board computers (SBCs) developed in the United Kingdom by the Raspberry Pi Foundation in association with Broadcom. The Raspberry Pi project originally leaned towards the promotion of teaching basic ...

s, Beagleboards, etc. shielded with NavIO, PXFMini, etc. or designed from scratch such as

NuttX NuttX is a free and open-source Real-Time Operating System (RTOS) with an emphasis on technical standards compliance and on having a small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the main governing standards in ...

, preemptive- RT Linux,

Xenomai Xenomai is a real-time development software framework cooperating with the Linux kernel to provide wikt:pervasive, pervasive, interface-agnostic, hard real-time computing support to user space application software seamlessly integrated into the Li ...

, Orocos-Robot Operating System or DDS-ROS 2.0. Civil-use open-source stacks include: * Agilicious (also open-source hardware) *

ArduCopter ArduPilot:Copter previously named APM:Copter or ArduCopter is the multicopter unmanned aerial vehicle version of the open-source ArduPilot autopilot platform. The free software approach from ArduCopter is similar to that of the Paparazzi Projec ...

* CrazyFlie * KKMultiCopter * MultiWii ** BaseFlight (forked from MultiWii) *** CleanFlight (forked from BaseFlight) **** BetaFlight (forked from CleanFlight) **** iNav (forked from CleanFlight) **** RaceFlight (forked from CleanFlight) * OpenPilot ** dRonin (forked from OpenPilot) **

LibrePilot LibrePilot is a Free software unmanned aerial vehicle project for model aircraft aimed at supporting both multi-rotor craft as well as fixed-wing aircraft. Initially founded by David Ankers, Angus Peart and Vassilis Varveropoulos in late 2009, und ...

(forked from OpenPilot) ** TauLabs (forked from OpenPilot) *

Paparazzi Paparazzi (, ; ; singular: masculine paparazzo or feminine paparazza) are independent photographers who take pictures of high-profile people; such as actors, musicians, athletes, politicians, and other celebrities, typically while subjects ...

PX4 autopilot PX4 autopilot is an open-source autopilot system oriented toward inexpensive autonomous aircraft. Low cost and availability enable hobbyist use in small remotely piloted aircraft. The project started in 2009 and is being further developed and us ...

** DroneCode (Umbrella organization managing PX4 within the Linux Foundation) Due to the open-source nature of UAV software, they can be customized to fit specific applications. For example, researchers from the Technical University of Košice have replaced the default control algorithm of the PX4 autopilot. This flexibility and collaborative effort has led to a large number of different open-source stacks, some of which are forked from others, such as CleanFlight, which is forked from BaseFlight and from which three other stacks are forked from.

Loop principles

UAVs employ open-loop, closed-loop or hybrid control architectures. *

Open loop Open or OPEN may refer to: Music * Open (band), Australian pop/rock band * The Open (band), English indie rock band * ''Open'' (Blues Image album), 1969 * ''Open'' (Gotthard album), 1999 * ''Open'' (Cowboy Junkies album), 2001 * ''Open'' (YF ...

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 A proportional–integral–derivative controller (PID controller or three-term controller) is a control loop mechanism employing feedback that is widely used in industrial control systems and a variety of other applications requiring continuou ...

is common. Sometimes, feedforward is employed, transferring the need to close the loop further.

Communications

UAVs use a

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

for control and exchange of video and other data. Early UAVs had only

narrowband Narrowband signals are signals that occupy a narrow range of frequencies or that have a small fractional bandwidth. In the audio spectrum, narrowband sounds are sounds that occupy a narrow range of frequencies. In telephony, narrowband is usua ...

uplink. Downlinks came later. These bi-directional narrowband radio links carried command and control (C&C) and

telemetry Telemetry is the in situ data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Gr ...

data about the status of aircraft systems to the remote operator. In most modern UAV applications, video transmission is required. So instead of having separate links for C&C, telemetry and video traffic, a

broadband In telecommunications, broadband is wide bandwidth data transmission which transports multiple signals at a wide range of frequencies and Internet traffic types, that enables messages to be sent simultaneously, used in fast internet connections. ...

link is used to carry all types of data. These broadband links can leverage

quality of service Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...

techniques and carry

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

traffic that can be routed over the Internet. The radio signal from the operator side can be issued from either: * Ground control – a human operating a

radio transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...

/receiver, a smartphone, a tablet, a computer, or the original meaning of a military ground control station (GCS). * 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 cellular mesh and LTE have been demonstrated and are in trials. * Another aircraft, serving as a relay or mobile control station military manned-unmanned teaming (MUM-T). Modern networking standards have explicitly considered drones and therefore include optimizations. The 5G standard has mandated reduced user plane latency to 1ms while using ultra-reliable and low-latency communications.

Autonomy

The level of autonomy in UAVs varies widely. UAV manufacturers often build in specific autonomous operations, such as: * Self-level: attitude stabilization on the pitch and roll axes. * Altitude hold: The aircraft maintains its altitude using barometric pressure and/or GPS data. * Hover/position hold: Keep level pitch and roll, stable yaw heading and altitude while maintaining position using

GNSS A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...

or inertial sensors. * Headless mode: Pitch control relative to the position of the pilot rather than relative to the vehicle's axes. * Care-free: automatic roll and yaw control while moving horizontally * Take-off and landing (using a variety of aircraft or ground-based sensors and systems; see also "

autoland In aviation, autoland describes a system that fully automates the landing procedure of an aircraft's flight, with the flight crew supervising the process. Such systems enable airliners to land in weather conditions that would otherwise be dangero ...

") * Failsafe: automatic landing or return-to-home upon loss of control signal * Return-to-home: Fly back to the point of takeoff (often gaining altitude first to avoid possible intervening obstructions such as trees or buildings). * Follow-me: Maintain relative position to a moving pilot or other object using GNSS,

image recognition Computer vision is an interdisciplinary scientific field that deals with how computers can gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to understand and automate tasks that the human ...

or homing beacon. * GPS waypoint navigation: Using GNSS to navigate to an intermediate location on a travel path. * Orbit around an object: Similar to Follow-me but continuously circle a target. * Pre-programmed

aerobatics Aerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in conventional passenger-carrying flights. The term is a portmanteau of "aerial" and "acrobatics". Aerobatics are performed in aeroplanes and glide ...

(such as rolls and loops) One approach to quantifying autonomous capabilities is based on

OODA The OODA loop is the cycle ''observe–orient–decide–act'', developed by military strategy, military strategist and United States Air Force Colonel John Boyd (military strategist), John Boyd. Boyd applied the concept to the combat operation ...

terminology, as suggested by a 2002 US

Air Force Research Laboratory The Air Force Research Laboratory (AFRL) is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of aerospace warfighting technologies, pl ...

report, and used in the table on the right. X-47B receives fuel from an Omega K-707 tanker while operating in the Atlantic Test Ranges

Full autonomy is available for specific tasks, such as airborne refueling or ground-based battery switching. Other functions available or under development include; collective flight, real-time collision avoidance, wall following, corridor centring, simultaneous localization and mapping and swarming,

cognitive radio A cognitive radio (CR) is a radio that can be programmed and configured dynamically to use the best wireless channels in its vicinity to avoid user interference and congestion. Such a radio automatically detects available channels in wireless spec ...

and

machine learning Machine learning (ML) is a field of inquiry devoted to understanding and building methods that 'learn', that is, methods that leverage data to improve performance on some set of tasks. It is seen as a part of artificial intelligence. Machine ...

. In this context, computer vision can play an important role for automatically ensuring flight safety.

Performance considerations

Flight envelope

UAVs can be programmed to perform aggressive maneuvers 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.

Endurance

Flight time against mass of small 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 The Wankel engine (, ) is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion. It was invented by German engineer Felix Wankel, and designed by German engineer Hanns-Dieter Paschke. ...

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. Proper drone cooling is essential for long-term drone endurance. Overheating and subsequent engine failure is the most common cause of drone failure.

Hydrogen fuel cells A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...

, using hydrogen power, may be able to extend the endurance of small UAVs, up to several hours. 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 In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be domi ...

. 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 A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

satellites. Likely applications include

weather drone A weather drone, or weather-sensing uncrewed aerial vehicle (UAV), – is a remotely piloted aircraft weighing less than 25 kg and carrying sensors that collect thermodynamic and kinematic data from the mid and lower atmosphere (e.g. up to 6 ...

s for weather monitoring, disaster recovery,

Earth imaging Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell i ...

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.

Reliability

Reliability improvements target all aspects of UAV systems, using resilience engineering and

fault tolerance Fault tolerance is the property that enables a system to continue operating properly in the event of the failure of one or more faults within some of its components. If its operating quality decreases at all, the decrease is proportional to the ...

techniques. Individual reliability covers robustness of flight controllers, to ensure safety without excessive redundancy to minimize cost and weight. Besides, dynamic assessment of

flight envelope In aerodynamics, the flight envelope, service envelope, or performance envelope of an aircraft or spacecraft refers to the capabilities of a design in terms of airspeed and load factor or atmospheric density, often simplified to altitude. The t ...

allows 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 crewed avionics software. Swarm resilience involves maintaining operational capabilities and reconfiguring tasks given unit failures.

Applications

In recent years, autonomous drones have begun to transform various application areas as they can fly beyond visual line of sight (BVLOS) while maximizing production, reducing costs and risks, ensuring site safety, security and regulatory compliance, and protecting the human workforce in times of a pandemic. They can also be used for consumer-related missions like package delivery, as demonstrated by

Amazon Prime Air Amazon Prime Air, or simply Prime Air, is a drone delivery service currently in development by Amazon. The service uses delivery drones to autonomously fly individual packages to customers. In 2020 the company, along with Zipline, Wingcopter ...

, and critical deliveries of health supplies. There are numerous civilian, commercial, military, and aerospace applications for UAVs. These include: ;General:

Recreation Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...

, Disaster relief,

archeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...

, conservation of

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

and

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

law enforcement Law enforcement is the activity of some members of government who act in an organized manner to enforce the law by discovering, deterring, rehabilitating, or punishing people who violate the rules and norms governing that society. The term en ...

crime In ordinary language, a crime is an unlawful act punishable by a State (polity), state or other authority. The term ''crime'' does not, in modern criminal law, have any simple and universally accepted definition,Farmer, Lindsay: "Crime, definit ...

, and

terrorism Terrorism, in its broadest sense, is the use of criminal violence to provoke a state of terror or fear, mostly with the intention to achieve political or religious aims. The term is used in this regard primarily to refer to intentional violen ...

. ;Commercial: Aerial surveillance,

filmmaking Filmmaking (film production) is the process by which a motion picture is produced. Filmmaking involves a number of complex and discrete stages, starting with an initial story, idea, or commission. It then continues through screenwriting, casti ...

journalism Journalism is the production and distribution of reports on the interaction of events, facts, ideas, and people that are the "news of the day" and that informs society to at least some degree. The word, a noun, applies to the occupation (profes ...

scientific research The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific m ...

surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...

, cargo transport,

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

manufacturing Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a r ...

Forestry Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forests, woodlands, and associated resources for human and environmental benefits. Forestry is practiced in plantations and natural stands. Th ...

, solar farming,

thermal energy The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, d ...

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

s and

Warfare

As of 2020, seventeen countries have armed UAVs, and more than 100 countries use UAVs in a military capacity. The global military UAV market is dominated by companies based in the United States, Turkey, China, Israel and Iran. By sale numbers, the US held over 60% military-market share in 2017. Top military UAV manufactures are including

General Atomics General Atomics is an American energy and defense corporation headquartered in San Diego, California, specializing in research and technology development. This includes physics research in support of nuclear fission and nuclear fusion energy. The ...

Lockheed Martin The Lockheed Martin Corporation is an American aerospace, arms, defense, information security, and technology corporation with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It ...

Northrop Grumman Northrop Grumman Corporation is an American multinational aerospace and defense technology company. With 90,000 employees and an annual revenue in excess of $30 billion, it is one of the world's largest weapons manufacturers and military techn ...

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...

, Baykar,

TAI Tai or TAI may refer to: Arts and entertainment *Tai (comics) a fictional Marvel Comics supervillain *Tai Fraiser, a fictional character in the 1995 film ''Clueless'' *Tai Kamiya, a fictional character in ''Digimon'' Businesses and organisations ...

, IAIO, CASC and CAIG. China has established and expanded its presence in military UAV market since 2010. Turkey also established and expanded its presence in military UAV market. Of the 18 countries that are known to have received military drones between 2010 to 2019, the top 12 all purchased their drones from China. According to a report of 2015, Israeli companies mainly focus on small surveillance UAV systems and by quantity of drones, Israel exported 60.7% (2014) of UAV on the market while the United States export 23.9% (2014). Between 2010 and 2014, there were 439 drones exchanged compared to 322 in the five years previous to that, among these only small fraction of overall trade – just 11 (2.5%) of the 439 are armed drones. The US alone operated over 9,000 military UAVs in 2014; among them more than 7000 are

RQ-11 Raven The AeroVironment RQ-11 Raven is a small hand-launched remote-controlled unmanned aerial vehicle (or SUAV) developed for the United States military, but now adopted by the military forces of many other countries. The RQ-11 Raven was originally i ...

miniature UAV A miniature UAV, small UAV (SUAV), or drone is an unmanned aerial vehicle small enough to be man-portable. Smallest UAVs are called micro air vehicle. Miniature UAVs range from micro air vehicles (MAVs) that can be carried by an infantryman, t ...

s. General Atomics is the dominant manufacturer with the Global Hawk and Predator/Mariner systems product-line. For intelligence and reconnaissance missions, the inherent stealth of micro UAV flapping-wing

s, imitating birds or insects, offers potential for covert surveillance and makes them difficult targets to bring down. UAVs are used for

, attack,

demining Demining or mine clearance is the process of removing land mines from an area. In military operations, the object is to rapidly clear a path through a minefield, and this is often done with devices such as mine plows and blast waves. By cont ...

, and

target practice In the military and in shooting, target practice are exercises in which weapons are shot at a target. The purpose of such exercises is to improve the aim or the weapons handling expertise of the person firing the weapon. Targets being shot at ...

Civil

The civilian (commercial and general) drone market is dominated by Chinese companies. Chinese drone manufacturer

DJI SZ DJI Technology Co., Ltd. or Shenzhen DJI Sciences and Technologies Ltd. ( zh, c=深圳大疆创新科技有限公司, p=Shēnzhèn Dà Jiāng Chuàngxīn Kējì Yǒuxiàn Gōngsī) in full, more popularly known as its trade name DJI, which s ...

alone had 74% of the civil market share in 2018, with no other company accounting for more than 5%, and with $11 billion forecast global sales in 2020. Following increased scrutiny of its activities, the US Interior Department grounded its fleet of DJI drones in 2020, while the Justice Department prohibited the use of federal funds for the purchase of DJI and other foreign made UAVs. DJI is followed by Chinese company Yuneec, US company 3D Robotics and French company

Parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoide ...

with a significant gap in market share. As of May 2021, 873,576 UAVs have been registered with the US FAA, of which 42% are categorized as commercial drones and 58% as recreational drones. 2018 NPD point to consumers increasingly purchasing drones with more advanced features with 33 percent growth in both the $500+ and $1000+ market segments. The civil UAV market is relatively new compared to the military one. Companies are emerging in both developed and developing nations at the same time. Many early stage startups have received support and funding from investors as is the case in the United States and by government agencies as is 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

Mavic and Matrice series of UAV for light reconnaissance mission since the civil drones are easier to use and have higher reliability. DJI drones is also the most widely used commercial unmanned aerial system that the US Army has employed. DJI surveillance drones have also been used by Chinese police in

Xinjiang Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as Sinkiang (, ), officially the Xinjiang Uygur Autonomous Region (XUAR), is an autonomous region of the People's Republic of China (PRC), located in the northwest ...

since 2017. The global UAV market will reach US$21.47 billion, with the Indian market touching the US$885.7 million mark, by 2021. Lighted drones are beginning to be used in nighttime

displays A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...

for artistic and advertising purposes.

Aerial photography

Drones are ideally suited to capturing aerial shots in photography and cinematography, and are widely used for this purpose. Small drones avoid the need for precise coordination between pilot and cameraman, with the same person taking on both roles. However, big drones with professional cine cameras, there is usually a drone pilot and a camera operator who controls camera angle and lens. For example, the AERIGON cinema drone which is used in film production in big blockbuster movies is operated by 2 people. Drones provide access to dangerous, remote or otherwise inaccessible sites.

Agriculture, forestry and environmental studies

As global demand for food production grows exponentially, resources are depleted, farmland is reduced, and agricultural labor is increasingly in short supply, there is an urgent need for more convenient and smarter agricultural solutions than traditional methods, and the agricultural drone and robotics industry is expected to make progress. Agricultural drones have been used in areas such as Africa to help build sustainable agriculture. The use of UAVs is also being investigated to help detect and fight wildfires, whether through observation or launching pyrotechnic devices to start backfires. UAVs are also now widely used to survey wildlife such as nesting seabirds, seals and even wombat burrows

Law enforcement

Police The police are a constituted body of persons empowered by a state, with the aim to enforce the law, to ensure the safety, health and possessions of citizens, and to prevent crime and civil disorder. Their lawful powers include arrest and t ...

can use drones for applications such as

search and rescue Search and rescue (SAR) is the search for and provision of aid to people who are in distress or imminent danger. The general field of search and rescue includes many specialty sub-fields, typically determined by the type of terrain the search ...

and

traffic monitoring Traffic reporting is the near real-time distribution of information about road conditions such as traffic congestion, detours, and traffic collisions. The reports help drivers anticipate and avoid traffic problems. Traffic reports, especially in ...

Safety and security

Threats

Nuisance

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. The first recorded instance of a drone collision with a

hot air balloon A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries ...

occurred on 10 August 2018 in

Driggs, Idaho Driggs is a city in the western United States in eastern Idaho, and is the county seat of Teton County. Part of the Jackson, WY-ID Micropolitan Statistical Area, it is located in Teton Valley, the headwaters of the Teton River. The populatio ...

, United States; although there was no significant damage to the balloon nor any injuries to its 3 occupants, the balloon pilot reported the incident to the

National Transportation Safety Board The National Transportation Safety Board (NTSB) is an independent U.S. government investigative agency responsible for civil transportation accident investigation. In this role, the NTSB investigates and reports on aviation accidents and incid ...

, stating that "I hope this incident helps create a conversation of respect for nature, the airspace, and rules and regulations". Unauthorized UAV flights into or near major airports have prompted extended shutdowns of commercial flights. Drones caused significant disruption at Gatwick Airport during December 2018, needing the deployment of the British Army. 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 The Lake Fire was a wildfire that burned in the San Bernardino National Forest. The fire started on June 17, 2015 and burned over 31,359 acres before it was fully contained on July 21, 2015. The fire was first reported at 4 p.m. on June 17, 2015 j ...

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.

Security vulnerabilities

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. Several security researchers have made public some vulnerabilities in 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 The Federal Trade Commission (FTC) is an independent agency of the United States government whose principal mission is the enforcement of civil (non-criminal) antitrust law and the promotion of consumer protection. The FTC shares jurisdiction ov ...

showed they were able to hack into three different consumer

s 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.

Aggression

UAVs could be loaded with dangerous payloads, and crashed into vulnerable targets. Payloads could include explosives, chemical, radiological 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".

Countermeasures

Counter unmanned air system

The malicious use of UAVs has led to the development of

counter unmanned air system An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...

(C-UAS) technologies. Automatic tracking and detection of UAVs from commercial cameras have become accurate thanks to the development of deep learning based machine learning algorithms. It is also possible to automatically identify UAVs across different cameras with different view points and hardware specification with re-identification methods. Commercial solutions such as the Aaronia AARTOS have been installed on major international airports. Anti-aircraft missile systems such as the

Iron Dome Iron Dome ( he, כִּפַּת בַּרְזֶל, Kippat Barzel) is a mobile all-weather air defense system developed by Rafael Advanced Defense Systems and Israel Aerospace Industries. The system is designed to intercept and destroy short- ...

are also being enhanced with C-UAS technologies. Utilising a smart UAV swarm to counter one or more hostile UAVs is also proposed.

Regulation

Regulatory bodies around the world are developing unmanned aircraft system traffic management solutions to better integrate UAVs into airspace. The use of unmanned aerial vehicles is becoming increasingly regulated by the

civil aviation authorities A civil aviation authority (CAA) is a national or supranational statutory authority that oversees the regulation of civil aviation, including the maintenance of an aircraft register. Role Due to the inherent dangers in the use of flight vehicles ...

of individual countries. Regulatory regimes can differ significantly according to drone size and use. The

International Civil Aviation Organization (ICAO) The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...

began exploring the use of drone technology as far back as 2005, which resulted in a 2011 report. France was among the first countries to set a national framework based on this report and larger aviation bodies such as the

FAA The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...

and the

EASA The European Union Aviation Safety Agency (EASA) is an agency of the European Union (EU) with responsibility for civil aviation safety. It carries out certification, regulation and standardisation and also performs investigation and monitori ...

quickly followed suit. In 2021, the FAA published a rule requiring all commercially-used UAVs and all UAVs regardless of intent weighing 250g or more to participate in Remote ID, which makes drone locations, controller locations, and other information public from takeoff to shutdown; this rule has since been challenged in the pending federal lawsuit '' RaceDayQuads v. FAA''.

Export controls

The export of UAVs or technology capable of carrying a 500 kg payload at least 300 km is restricted in many countries by the

Missile Technology Control Regime The Missile Technology Control Regime (MTCR) is a multilateral export control regime. It is an informal political understanding among 35 member states that seek to limit the proliferation of missiles and missile technology. The regime was formed ...

References

Citations

Bibliography

*Axe, David. ''Drone War Vietnam.'' Pen & Sword, Military. Great Britain. (2021). ISBN 978 1 52677 026 4 * *

External links

How Intelligent Drones Are Shaping the Future of Warfare
''Rolling Stone Magazine'' {{DEFAULTSORT:Unmanned Aerial Vehicle Wireless Avionics Robotics Emerging technologies Articles containing video clips

Terminology

Classification types

Range and endurance

Size

Weight

Degree of autonomy

Altitude

Composite criteria

History

Early drones

World War II

Postwar period

Modern UAVs

Design

Aircraft configuration

Propulsion

Ornithopters – wing propulsion

Computer control systems

Architecture

Sensors

Actuators

Software

Loop principles

Communications

Autonomy

Performance considerations

Flight envelope

Endurance

Reliability

Applications

Warfare

Civil

Aerial photography

Agriculture, forestry and environmental studies

Law enforcement

Safety and security

Threats

Nuisance

Security vulnerabilities

Aggression

Countermeasures

Counter unmanned air system

Regulation

Export controls

See also

References

Citations

Bibliography

Further reading

External links