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US Military Dictionary:

unmanned aerial vehicle


UAV

An aerial vehicle that does not require a human operator and can fly independently or be operated remotely, is either recoverable or expendable, and is capable of carrying a lethal or nonlethal payload.

See the Introduction, Abbreviations and Pronunciation for further details.

 
 
Intelligence Encyclopedia: Unmanned Aerial Vehicles (UAVs)

Israel was the first nation to make significant use of unmanned reconnaissance drones in combat during operations in Lebanon in 1982. The United States forces began full deployment and use of unmanned aerial vehicles (UAVs) and related technology in the 1990s and UAVs—especially the Predator and Global Hawk—were extensively used by U.S. forces during Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom.

Tactical Uses of Uavs

UAVs can fly in areas where air supremacy is not complete or air defenses have not been fully suppressed. UAV craft can also operate in biologically or chemically contaminated areas. In addition, UAVS offer a chance to conduct battle damage assessments—critical for further mission planning—without further risk to pilots.

As of May 2003 more than 1500 UAV sorties had been flown in Afghanistan and UAV craft destroyed, or assisted in the destruction of, nearly a thousand targets. In addition to the capability of some UAVs to fire Hellfire missiles, UAV can paint targets with lasers that guide other weapons systems.

Uav Capabilities

The Predator flies at medium altitudes and is capable of long reconnaissance and surveillance missions. In conjunction with weapons systems, Predator craft are also used for target acquisition.

The Global Hawk, is capable of operating at higher altitudes (in excess of 60,000 ft) on and features an integrated sensor system that enhance its intelligence, surveillance, and reconnaissance capabilities.

The U.S. Navy operates the Pioneer UAV. Designed to operate over open ocean, the Pioneer design incorporates a low radar cross section and reduced infrared signature. Pioneer craft were first used during operations in Grenada and strikes against Libya.

The Shadow UAV offers day and night surveillance capability and can carry a 330 lbs. Payload while operating at 10,000 ft. The U.S. Army uses Shadow UAVs to call in or lock on (calibrate) artillery attacks.

UAV use has also spurred advances in miniaturized synthetic aperture radar that reduces weight but still offers high stationary and moving target resolution (i.e. radar that can discriminate targets separated by less than 18 inches (.5 m).

UAVs as platforms for weapons of mass destruction or terrorism. Prior to its being eliminated by U.S. forces, U.S. officials claimed that Saddam Hussein's Iraqi regime had developed and tested a limited number of UAVs capable of delivering biological agents.

In 2003, Hamas operatives were killed as they were preparing to test an unmanned aerial vehicle (UAV) purchased from illegal arms dealers. The craft exploded before Hamas could carry out a planned attack against a target inside Israel. Hamas spokesmen subsequently claimed that they been fooled into purchasing a booby-trapped UAV by the Israeli Security Agency ISA (Shin Bet).

Western press organizations have also carried reports that Palestinian agents have attempted purchases of model aircraft from suppliers in Europe with the intent to develop a crude but UAV capability. One factor limiting these types of operations is that typical hobbist UAVs require line-of-sight control of the aircraft and are therefore incapable of navigating with precision over rugged terrain or over great distances.

UAV use in intelligence operations and current research. In November, 2002, a CIA-operated Predator operating over Yemen fired a missile that killed bin Laden's top lieutenant in Yemen, Qaed Salim Sinan al-Harethi, and five other al-Qaeda suspects.

DARPA planned advancement of the Unmanned Combat Air Vehicle (UCAV) and Unmanned Combat Armed Rotorcraft (UCAR) is designed to enhance the ability to remotely suppress enemy air defenses, conduct extended surveillance in hostile territory, and pursue armed reconnaissance and attack missions.

A milestone in unmanned aviation, in 2002, the U.S. flew an unmanned plane on a trans-Pacific flight from California to Australia.

DoD and Northrop Grumman engineers are currently refining the Eurohawk for advanced electronics and signals intelligence operations. France is developing the Système de Drone Tactique Interimaire (SAGEM) and United Kingdom is developing a craft termed "Watchkeeper" to replace the Phoenix.

Further Reading

Electronic

Airborne Autonomous Systems. Unmanned Aircrft.<http://www.unmannedaircraft.com/> (May 12, 2003).

American Forces Press Service, Garamone, Jim. "From U.S. Civil War to Afghanistan: A Short History of UAVs." April, 16, 2002. <http://www.defenselink.mil/news/Apr2002/n04162002_200204163.html> (May 12, 2003).

 
Military Dictionary: unmanned aerial vehicle

(DOD) A powered, aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or nonlethal payload. Ballistic or semiballistic vehicles, cruise missiles, and artillery projectiles are not considered unmanned aerial vehicles. Also called UAV.

 
Wikipedia: unmanned aerial vehicle

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. They are also used in a small but growing number of civil applications such as firefighting where a human observer would be at risk, police observation of civil disturbances and scenes of crimes, and reconnaissance support in natural disasters.

There are a wide variety UAV shapes, sizes, configurations, and characteristics. 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.

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) originally introduced by the US Navy to reflect the fact that these are not just aircraft, but systems including ground stations and other elements.

History

The earliest UAV was A. M. Low's "Aerial Target" of 1916.[1] A number of remote-controlled airplane advances followed, including the Hewitt-Sperry Automatic Airplane, during and after World War I, including the first scale RPV, developed by film star and model airplane enthusiast Reginald Denny in 1935.[2] More were made in the technology rush during the Second World War; these were used both to train anti-aircraft gunners and to fly attack missions. Jet engines were applied after WW2, in such types as the Teledyne Ryan Firebee I of 1951, while companies like Beechcraft also got in the game with their Model 1001 for the United States Navy in 1955.[3] Nevertheless, they were little more than remote controlled airplanes until the Vietnam Era.

Front view of a Predator (Reno Air Show)
Enlarge
Front view of a Predator (Reno Air Show)

With the maturing and miniaturization of applicable technologies as seen in the 1980s and 1990s, interest in UAVs grew within the higher echelons of the US military. UAVs were seen to offer the possibility of cheaper, more capable fighting machines that can be used without risk to aircrews. Initial generations were primarily surveillance aircraft, but some were fitted with weaponry (such as the MQ-1 Predator, which utilized AGM-114 Hellfire air-to-ground missiles). An armed UAV is known as an Unmanned Combat Air Vehicle (UCAV).

In the future, it is expected more and more roles will be performed by unmanned aircraft. Bombing and ground attack will be added to the surveillance role. Air-to-air combat will likely be the last domain of the human pilot. Search and rescue could be performed by UAVs with heat sensors to help find humans lost in the wilderness, trapped in collapsed buildings, or adrift at sea.

UAV classification

UAVs typically fall into one of six functional 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)
  • Logistics - UAVs specifically designed for cargo and logistics operation
  • 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

They can also be categorised in terms of range/altitude and the following has been advanced as relevant at such industry events as ParcAberporth Unmanned Systems forum.

  • Handheld  ft ( m) altitude, about 2 km range
  • Close  ft ( m) altitude, up to 10 km range
  • NATO type  ft ( m) altitude, up to 50 km range
  • Tactical  ft ( m) altitude, about 160 km range
  • MALE (medium altitude, long endurance) up to  ft ( m) and range over 200 km
  • HALE (high altitude, long endurance) over 30,000 ft and indefinite range
  • HYPERSONIC high-speed, supersonic (Mach 1-5) or hypersonic (Mach 5+)  ft ( m) or suborbital altitude, range over 200km
  • ORBITAL low earth orbit (Mach 25+)
  • CIS Lunar Earth-Moon transfer


The U.S. Military employs a tier system for categorizing its UAVs.

U.S. Military UAV classifications

The modern concept of U.S. Military 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.

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.[4]
  • 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  feet ( m), less than  knots ( km/h) airspeed,  nautical mile ( km) 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."[5][6]

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: For two decades, the role of medium range tactical UAV was filled by the Pioneer UAV. In July 2007, the Marine Corps announced its intention to retire the aging Pioneer fleet and transition to the Shadow® Tactical Unmanned Aircraft System by AAI Corporation. The first Marine Shadow systems have already been delivered, and training for their respective Marine Corps units is underway.[7][8]

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 Extended Range Multi-Purpose (ERMP) MQ-1C Warrior.

Future Combat Systems (FCS) (US Army) classes

  • Class I: For small units. Role to be filled by all new UAV with some similarity to Micro Air Vehicle.
  • 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.

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.[9] 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 Small Unmanned Aircraft Systems (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.

UAV functions

UAVs perform a wide variety of functions. The majority of these functions are some form of remote sensing. Less common UAV functions include interaction and transport. To create viable new UAV systems, these functions are integrated to allow the UAV to perform complex tasks within its given application.

Remote Sensing

UAV remote sensing functions include electromagnetic spectrum sensors, biological sensors, and chemical sensors. A UAV's electromagnetic sensors typically include visual spectrum, infrared, or near infrared cameras as well as radar systems. Other electromagnetic wave detectors such as microwave and ultraviolet spectrum sensors may also be used, but are uncommon. Biological sensors are sensors capable of detecting the airborne presence of various microorganisms and other biological factors. Chemical sensors use laser spectroscopy to analyze the concentrations of each element in the air.

Interaction

UAV interaction functions intentionally alter the UAV's environment in some way. These functions include attacking, taking samples, delivering a payload, and repairing a given structure.

Transport

UAVs can transport goods using various means based on the configuration of the UAV itself. Most payloads are stored in an internal payload bay somewhere in the airframe. For many helicopter configurations, external payloads can be tethered to the bottom of the airframe. With fixed wing UAVs, payloads can also be attached to the airframe, but aerodynamics of the aircraft with the payload must be assessed. For such situations, payloads are often enclosed in aerodynamic pods for transport.

Scientific Research Unmanned aircraft are uniquely capable of penetrating areas which may be too dangerous for piloted craft. The National Oceanic and Atmospheric Administration (NOAA) began utilizing the Aerosonde® unmanned aircraft system in 2006 as a hurricane hunter. AAI Corporation subsidiary Aerosonde Pty Ltd. of Victoria, Australia, designs and manufactures the 35-pound system, which can fly into a hurricane and communicate near real-time data directly to the National Hurricane Center in Florida. Beyond the standard barometric pressure and temperature data typically cultivated from manned hurricane hunters, the Aerosonde system provides measurements far closer to the water’s surface than previously captured. Further applications for unmanned aircraft can be explored once solutions have been developed for their accommodation within national airspace, an issue currently under discussion by the Federal Aviation Administration.

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.[10] Northrop Grumman and General Atomics are the dominant manufacturers in this industry, on the strength of the Global Hawk and Predator/Mariner systems.[10] 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.[10] European market share represented just 4% of global revenue in 2006.[10]

Degree of autonomy

Rear view of a Predator (Reno Air Show)
Enlarge
Rear view of a Predator (Reno Air Show)
UAV monitoring and control at CBP
Enlarge
UAV monitoring and control at CBP

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 is important to UAV development falls 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
  • Path planning: Determining an optimal path for vehicle to go while meeting certain objectives and mission constraints, such as obstacles or fuel requirements
  • Trajectory Generation (sometimes called Motion planning): Determining an optimal control maneuver to take to follow a given path or to go from one location to another
  • Trajectory Regulation: The specific control strategies required to constrain a vehicle within some tolerance to a trajectory
  • 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.

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.

Interoperable UAV technologies became essential as systems proved their mettle in military operations, taking on tasks too challenging or dangerous for warfighters. NATO addressed the need for commonality through STANAG (Standardization Agreement) 4586. According to a NATO press release, the agreement began the ratification process in 1992. Its goal was to allow allied nations to easily share information obtained from unmanned aircraft through common ground control station technology. STANAG 4586-compliant aircraft are equipped to translate information into standardized message formats; likewise, information received from other compliant aircraft can be transferred into vehicle-specific messaging formats for seamless interoperability. Amendments have since been made to the original agreement, based on expert feedback from the field and an industry panel known as the Custodian Support Team. Edition Two of STANAG 4586 is currently under review. There are many systems available today that comply with STANAG 4586, including products by industry leaders such as AAI Corporation, CDL Systems, and Raytheon, all three of which are members of the Custodian Support Team for this protocol.

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 US Air Force is promoting research that should end in an inflight UAV refueling capability, which should be available by 2009.

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

QinetiQ Zephyr Solar Electric 54 hours September 2007 QinetiQ press release

New Scientist article

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

TIHA (Turkish Unmanned Aerial Vehicle) 24 hours Prototypes: 24 December 2004 Serial Production: To be complete by 2010 TIHA Program

Turkish Aerospace Industries UAV Products

Existing UAV systems

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.


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.
  • During the Gulf War, Iraqi Army forces surrendered to the UAVs of the USS Wisconsin.
  • In October, 2002, a few days before the U.S. Senate vote on the Authorization for Use of Military Force Against Iraq Resolution, about 75 senators were told in closed session that Saddam Hussein had the means of delivering biological and chemical weapons of mass destruction by UAV drones that could be launched from ships off the Atlantic coast to attack U.S. eastern seaboard cities. Colin Powell suggested in his presentation to the United Nations that they had been transported out of Iraq and could be launched against the U.S. Actually, Iraq had no fleet of UAVs nor any capability of putting UAVs on ships. Neither did Iraq have any chemical weapons. [11] Iraq's UAV fleet consisted of only a few outdated Czech training drones.[12] At the time, there was a vigorous dispute within the intelligence community as to whether CIA's conclusions about Iraqi UAVs were accurate. The U.S. Air Force agency most familiar with UAVs denied outright that Iraq possessed any offensive UAV capability.[13]
  • In December 2002, the first ever dogfight involving a UAV occurred when an Iraqi MiG-25 and a U.S. RQ-1 Predator fired missiles at each other. The MiG's missile destroyed the Predator. [14]

References

  1. ^ Taylor, A. J. P. Jane's Book of Remotely Piloted Vehicles.
  2. ^ Taylor, A. J. P. Jane's Book of Remotely Piloted Vehicles.
  3. ^ Taylor, A. J. P. Jane's Book of Remotely Piloted Vehicles.
  4. ^ History of Unmanned Aerial Vehicles
  5. ^ Comparison of USAF Tier II, II+ and III- systems
  6. ^ http://www.edwards.af.mil/articles98/docs_html/splash/may98/cover/Tier.htm USAF Tier system
  7. ^ USMC powerpoint presentation of tier system
  8. ^ Detailed description of USMC tier system
  9. ^ http://www.acq.osd.mil/usd/Roadmap%20Final2.pdf#search=%22Dod%20UAS%20Roadmap%202005%22
  10. ^ a b c d "UAVs on the Rise." Dickerson, L. Aviation Week & Space Technology. January 15, 2007.
  11. ^ Senator Bill Nelson (January 28, 2004) "New Information on Iraq's Possession of Weapons of Mass Destruction", Congressional Record
  12. ^ Lowe, C. (December 16, 2003) "Senator: White House Warned of UAV Attack," Defense Tech
  13. ^ Hammond, J. (November 14, 2005) "The U.S. 'intelligence failure' and Iraq's UAVs" The Yirmeyahu Review
  14. ^ Pilotless Warriors Soar To Success, www.cbsnews.com, 25 April 2004. Accessed 21 April 2007.

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US Military Dictionary. The Oxford Essential Dictionary of the U.S. Military. Copyright © 2001, 2002 by Oxford University Press, Inc. All rights reserved.  Read more
Intelligence Encyclopedia. Encyclopedia of Espionage, Intelligence, and Security. Copyright © 2004 by The Gale Group, Inc. All rights reserved.  Read more
Military Dictionary. US Department of Defense Dictionary of Military and Associated Words, 2003.  Read more
Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Unmanned aerial vehicle" Read more

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