Unmanned aerial vehicle

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An unmanned aerial vehicle (UAV) is an aircraft with no onboard pilot. UAVs can be remote controlled or fly autonomously based on pre-programmed flight plans or more complex dynamic automation systems. UAVs are currently used in a number of military roles, including reconnaissance and attack.

The acronym UAV has been expanded in some cases to UAVS (Unmanned Aircraft Vehicle System). The Federal Aviation Administration has adopted the generic class Unmanned Aircraft System (UAS) to reflect the fact that these are not just aircraft, but systems including ground stations and other elements.

For the purposes of this article, and to distinguish UAVs from missiles, a UAV is defined as being capable of controlled, sustained level flight and powered by a jet or reciprocating engine. Cruise missiles are not classed as UAVs, because, like many other guided missiles, the vehicle itself is a weapon that is not reused even though it is also unmanned and might in some cases be remotely guided.

Contents 1 History 2 Design and development considerations 2.1 Degree of autonomy 2.2 Endurance 2.3 UAV types 2.4 U.S. UAV tier system 2.4.1 US Air Force tiers 2.4.2 US Marine Corp tiers 2.4.3 US Army tiers 2.4.4 Future Combat Systems (FCS) (US Army) classes 3 Unmanned Aircraft System 4 UAV models 5 Trivia 6 References 7 See also 8 External links

[edit] History

Main article: History of unmanned aerial vehicles

The concept of the UAV is thought to have been created by Leonardo Da Vinci in 1488. Many sketches penned by Da Vinci himself have been discovered to suggest this. It is believed he called the plane "Non il volo umano", which roughly translates to "Non-human flight". Despite Da Vinci's elaborate concept, the idea was not put into action until much, much later. The earliest such aircraft, the Hewitt-Sperry Automatic Airplane was developed during and after World War I, and a number of advances were made with the technology rush that accompanied the Second World War; these were used both to train anti-aircraft gunners and to fly attack missions. Nevertheless, they were little more than full-sized remote controlled airplanes until the Vietnam era. Lately, with the maturing and miniaturization of applicable technologies, interest in such craft has grown within the higher echelons of the US military, as they offer the possibility of cheaper, more capable fighting machines that can be used without risk to aircrews. Initial generations have primarily been surveillance aircraft, but some have already been fitted with weaponry (such as the MQ-1 Predator, which utilizes AGM-114 Hellfire air-to-ground missiles). The military envisions that more and more roles will be performed by unmanned aircraft, initially bombing and ground attack, with air-to-air combat expected to be the last domain of the fighter pilot for now. An armed UAV is known as an Unmanned Combat Air Vehicle (UCAV). Another area of interest in the field of UAVs is to utilize the aircraft as a search and rescue instrument. Heat sensors could be put in place to help find humans trapped in mountain ranges, collapsed buildings or lost at sea.

[edit] Design and development considerations

UAV design and production is a global activity, with manufacturers all across the world. The United States and Israel were initial pioneers in this technology, and U.S. manufacturers have a market share of over 60% in 2006, with U.S. market share due to increase by 5-10% through 2016.^[1] Northrop Grumman and General Atomics are the dominant manufacturers in this industry, on the strength of the Global Hawk and Predator/Mariner systems.^[1] Israeli and European manufacturers form a second tier due to lower indigenous investments, and the governments of those nations have initiatives to acquire U.S. systems due to higher levels of capability.^[1] European market share represented just 4% of global revenue in 2006.^[1]

[edit] Degree of autonomy

Some early UAVs are called drones because they are no more sophisticated than a simple radio controlled aircraft being controlled by a human pilot (sometimes called the operator) at all times. More sophisticated versions may have built-in control and/or guidance systems to perform low level human pilot duties such as speed and flight path stabilization, and simple prescripted navigation functions such as waypoint following.

From this perspective, most early UAVs are not autonomous at all. In fact, the field of air vehicle autonomy is a recently emerging field, whose economics is largely driven by the military to develop battle ready technology. Compared to the manufacturing of UAV flight hardware, the market for autonomy technology is fairly immature and undeveloped. Because of this, autonomy has been and may continue to be the bottleneck for future UAV developments, and the overall value and rate of expansion of the future UAV market could be largely driven by advances to be made in the field of autonomy.

Autonomy technology that will become important to future UAV development fall under the following categories:

• Sensor fusion: Combining information from different sensors for use on board the vehicle
• Communications: Handling communication and coordination between multiple agents in the presence of incomplete and imperfect information
• Motion planning (also called Path planning): Determining an optimal path for vehicle to go while meeting certain objectives and constraints, such as obstacles
• Trajectory Generation: Determining an optimal control maneuver to take to follow a given path or to go from one location to another
• Task Allocation and Scheduling: Determining the optimal distribution of tasks amongst a group of agents, with time and equipment constraints
• Cooperative Tactics: Formulating an optimal sequence and spatial distribution of activities between agents in order to maximize chance of success in any given mission scenario

Autonomy is commonly defined as the ability to make decisions without human intervention. To that end, the goal of autonomy is to teach machines to be "smart" and act more like humans. The keen observer may associate this with the development in the field of artificial intelligence made popular in the 1980s and 1990s such as expert systems, neural networks, machine learning, natural language processing, and vision. However, the mode of technological development in the field of autonomy has mostly followed a bottom-up approach, and recent advances have been largely driven by the practitioners in the field of control science, not computer science. Similarly, autonomy has been and probably will continue to be considered an extension of the controls field. In the foreseeable future, however, the two fields will merge to a much greater degree, and practitioners and researchers from both disciplines will work together to spawn rapid technological development in the area.^{[citation needed]}

To some extent, the ultimate goal in the development of autonomy technology is to replace the human pilot. It remains to be seen whether future developments of autonomy technology, the perception of the technology, and most importantly, the political climate surrounding the use of such technology, will limit the development and utility of autonomy for UAV applications.

Under the NATO standardization policy 4586 all NATO UAVs will have to be flown using the Tactical Control System (TCS) a system developed by the software company Raytheon.

[edit] Endurance

Because UAVs are not burdened with the physiological limitations of human pilots, they can be designed for maximized on-station times. The maximum flight duration of unmanned aerial vehicles varies widely. Internal combustion engine aircraft endurance depends strongly on the percentage of fuel burned as a fraction of total weight (the Breguet endurance equation), and so is largely independent of aircraft size. Solar electric UAVs hold the potential for unlimited flight, a concept championed by the Helios Prototype, which unfortunately was destroyed in a 2003 crash. One of the major problems with UAVs currently is that there is no capability for in flight refuelling. Currently the Air Force is promoting research that should end in a UAV refueling capability, which should be available within two years.

Notable high endurance flights

UAV	Flight time	Date	Notes
Boeing Condor	58 hours, 11 minutes	?	The aircraft is currently in the Hiller Aviation Museum, CA. Hiller Aviation Museum reference to the flight
IAI Heron	52 hours	?	NOVA PBS TV program reference IAI reference
AC Propulsion Solar Electric	48 hours, 11 minutes	June 3, 2005	AC Propulsion release describing the flight
MQ-1 Predator	40 hours, 5 minutes	?	UAV Forum reference Federation of American Scientists reference
GNAT-750	40 hours	1992	Directory of US Military Rockets and Missiles reference to the flight UAV Endurance Prehistory reference
Aerosonde	38 hours, 48 minutes	May 3, 2006	Aerosonde release on the flight
I-GNAT	38 hours, landed with 10 hour reserve	?	General Atomics reference to the flight
RQ-4 Global Hawk	30 hours, 24 minutes	?	Space Daily story on the flight Rand Corporation report

[edit] UAV types

UAVs typically fall into one of five categories (although multi-role airframe platforms are becoming more prevalent):

• Target and decoy - providing ground and aerial gunnery a target that simulates an enemy aircraft or missile
• Reconnaissance - providing battlefield intelligence
• Combat - providing attack capability for high-risk missions (see Unmanned Combat Air Vehicle)
• Research and development - used to further develop UAV technologies to be integrated into field deployed UAV aircraft
• Civil and Commercial UAVs - UAVs specifically designed for civil and commercial applications.

[edit] U.S. UAV tier system

The modern concept of UAVs is to have the various aircraft systems work together in support of personnel on the ground. The integration scheme is described in terms of a "Tier" system, and is used by military planners to designate the various individual aircraft elements in an overall usage plan for integrated operations. The Tiers do not refer to specific models of aircraft, but rather roles for which various models and their manufacturers competed. The U.S. Air Force and the U.S. Marine Corps each has its own tier system, and the two systems are themselves not integrated.

[edit] US Air Force tiers

• Tier N/A: Small/Micro UAV. Role filled by BATMAV (Wasp Block III). [1]
• Tier I: Low altitude, long endurance. Role filled by the Gnat 750.^[2]
• Tier II: Medium altitude, long endurance (MALE). Role currently filled by the MQ-1 Predator and MQ-9 Reaper.
• Tier II+: High altitude, long endurance conventional UAV (or HALE UAV). Altitude: 60,000 to 65,000 feet, less than 300 knots airspeed, 3,000 nautical mile radius, 24 hour time-on-station capability. Complementary to the Tier III- aircraft. Role currently filled by the RQ-4 Global Hawk.
• Tier III-: High altitude, long endurance low-observable UAV. Same parameters as, and complementary to, the Tier II+ aircraft. The RQ-3 DarkStar was originally intended to fulfill this role before it was "terminated."^[3][4]

[edit] US Marine Corp tiers

• Tier N/A: Micro UAV. Wasp is targeted for this role, now more so given commonality with USAF BATMAV. [2]
• Tier I: Role currently filled by the Dragon Eye but transitioning to the RQ-11B Raven B
• Tier II: Role currently filled by the Scan Eagle and, to some extent, the RQ-2 Pioneer
• Tier III: Role currently filled by the Pioneer, although USMC planners do not view this aircraft as meeting future Tier III requirements.^[5][6]

[edit] US Army tiers

• Tier I: Small UAV. Role filled by the RQ-11A/B Raven.
• Tier II: Short Range Tactical UAV. Role filled by the RQ-7A/B Shadow 200.
• Tier III: Medium Range Tactical UAV. Role currently filled by the RQ-5A / MQ-5A/B Hunter and i-Gnat, but transitioning to the Extented Range Multi-Purpose (ERMP) Warrior.

[edit] Future Combat Systems (FCS) (US Army) classes

• Class I: For small units. Role to be filled by the Micro Air Vehicle, still in development.
• Class II: For companies. (cancelled.) [3]
• Class III: For battalions. (cancelled.) [4]
• Class IV: For brigades. Role to be filled by the RQ-8A/B / MQ-8B Fire Scout.

[edit] Unmanned Aircraft System

UAS, or Unmanned Aircraft System, is the official U.S. Department of Defense term for an Unmanned Aerial Vehicle. The term was first officially used in the DoD 2005 Unmanned Aircraft System Roadmap 2005–2030.^[7] Many people have mistakenly used the term Unmanned 'Aerial' System, or Unmanned 'Air Vehicle' System.

Officially, the term 'Unmanned Aerial Vehicle' was changed to 'Unmanned Aircraft System' to reflect the fact that these complex systems include ground stations and other elements besides the actual air vehicles. The term UAS, however, is not widely used, as the term UAV has become part of the modern lexicon.

The military role of UAS is growing at unprecedented rates. In 2005, tactical and theater level unmanned aircraft (UA) alone had flown over 100,000 flight hours in support of Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF). Rapid advances in technology are enabling more and more capability to be placed on smaller airframes which is spurring a large increase in the number of SUAS being deployed on the battlefield. The use of SUAS in combat is so new that no formal DoD wide reporting procedures have been established to track SUAS flight hours. As the capabilities grow for all types of UAS, nations continue to subsidize their research and development leading to further advances enabling them to perform a multitude of missions. UAS no longer only perform intelligence, surveillance, and reconnaissance (ISR) missions, although this still remains their predominant type. Their roles have expanded to areas including electronic attack (EA), strike missions, suppression and/or destruction of enemy air defense ([SEAD]/DEAD), network node or communications relay, combat search and rescue (CSAR), and derivations of these themes. These UAS range in cost from a few thousand dollars to tens of millions of dollars, and the aircraft used in these systems range in size from a Micro Air Vehicle (MAV) weighing less than one pound to large aircraft weighing over 40,000 pounds.

[edit] UAV models

UAVs have been developed and deployed by many countries around the world. For a list of models by country, see List of unmanned aerial vehicles.

[edit] Trivia

• UAVs have been used in many episodes of the science fiction television series Stargate SG-1, and a sentient Unmanned Combat Aerial Vehicle (UCAV) was a central figure in the action film Stealth.
• Marilyn Monroe, then named Norma Jeane Baker, was discovered while working in the factory building the first mass-produced UAVs, the OQ-2 Radioplane.
• Early UAVs (called RPVs) feature heavily in the novel The Last Raven by Craig Thomas. The camera is removed and replaced with a remotely-detonated warhead, allowing them to carry out a kamikaze-style attack on a Soviet military plane.
• On March 20, 2007, an unmanned Border Protection agency UAV detected and led agents to six suspected aliens, including Mexican national Leopoldo Aparicio-Lopez, who had been wanted in Washington state on charges of third-degree rape of a child. Aparicio-Lopez was one of six suspected illegals in the group, and 395 pounds of marijuana were also seized during the arrest, federal officials said.^[8]

[edit] References

[edit] See also

• History of unmanned aerial vehicles
• Unmanned Combat Air Vehicle (UCAV)
• Unmanned Aircraft System (or UAS)
• UAV Battlelab
• International Aerial Robotics Competition
• Unmanned Ground Vehicle
• Remotely Operated Vehicle (or ROV)
• Autonomous Underwater Vehicle
• Intelligence, Surveillance, Target Acquisition, and Reconnaissance (or ISTAR)
• Aerobot

[edit] External links

• Gyrodyne UAV History
• UAV MarketSpace - a comprehensive UAV and UAS Resource Website
• Picture of Swiss UAV in Finnish Army
• "Human Pilots: Who Needs 'Em?" — Wired News, 23 November 2003
• Future Possible Uses and Designs of UAVs from the World Think Tank
• AUVS International Aerial Robotics Competition — Home page by Robert Michelson, AUVS International / Georgia Tech Research Institute
• Defense Update coverage of UAV Mission Systems
• Defense Update reports about UAV employment in Persistent Surveillance
• UAVs at IAI/Malat
• UAVs over Kosovo - did the Earth move? Defense Systems Daily article about NATO UAV operations in Kosovo 1999, includes a list of losses
• UAV operations An Indian Journal of Aerospace Medicine Analysis of Human Factor Issues in UAV accidents
• The UK and US governments are sharing the latest technology for unmanned aerial vehicles (UAV)
• Civilian UAV development
• Autonomy Technologies for Rotorcraft and Fixed Wing Platforms
• TAI's Tiha MALE UAV
• DoD UAS Roadmap 2005-2030
• FAA UAS FAQ
• History of WWI-era UAVs
• White paper detailing development and flight test of experimental tail-sitter UAV
• Raven UAV (tiny drone) launch from building in Najaf, Iraq
• A Fully Autonomous Helicopter Flight Demonstration Video
• Officially confirmed / documented NATO UAV losses in the Balkans
• UAV Focus - Daily News and Information for the UAV and UAS Industry
• The Remote Control Aerial Photography Association, commercial UAS operators
• Opensource UAV control system