Kevin Teusch

From Advanced Military Vehicle to Everyday Life: The Evolution of the UAV

Drawing from many engineering disciplines, Unmanned Aerial Vehicles, or UAVs, have become a highly demanded military tool used to gather intelligence and mount attacks. In recent years, UAVs have become smaller and more versatile, allowing them to be used in even more applications both in the military and domestically. UAVs have become cheaper and easier to use, and because of that their application extends far beyond the military. In the future as the technology progresses, UAVs will likely be used for a wide variety of purposes and may someday dominate the city skies.

Introduction

Ever since their introduction into the military's arsenal of aerial vehicles, the Unmanned Aerial Vehicle, known as a UAV or drone, has slowly reshaped modern warfare. In the last decade, UAV technology has rapidly progressed, and as a result UAVs have been used in a wider range of applications, both foreign and domestic. Because of advancements in aerodynamics, propulsion systems, stealth technology, and telecommunications, UAVs have become one of the most demanded military vehicles. The United States currently has over 7,000 active drones, compared to less than 100 only a decade ago. The US Air Force expects the number of multirole drones, similar to the MQ-9 Reaper, to quadruple in the in the next decade [1]. In the media UAVs are portrayed as remote killing machines, but their importance reaches far beyond that. Because of their versatility, UAVs have nearly endless applications outside the military. With recent advancements in UAV technology, UAVs have become cheaper and more practical, and someday they will likely become a part of daily life.

History of UAVs

The use of unmanned vehicles in the military is not a new idea. Their use dates back to 1849 when Austria attacked the city of Venice with balloons armed with bombs that were detonated by timed fuses. This type of weapon was not very successful and never gained widespread use. Due to the lack of radio technology, remote controlled vehicles were nonexistent in this time. The first advancement in radio controlled vehicles did not come until 1898 when the famous inventor Nikola Tesla demonstrated his "teleautomaton," in which he was able to wirelessly control a small boat. Tesla's work along with the work or other inventors laid the foundation of modern remote control technology [2].

Because of the focus on land warfare, UAV technology progressed slowly in the first half of the 20th century. Remotely controlled aircraft were first used in World War II. These rudimentary UAVs consisted of modified manned aircraft that were used similarly to cruise missiles. A pilot would bring the aircraft to cruising altitude before bailing out and transferring the controls to

nearby plane through radio. The plane could then be flown into enemy targets. However this type of UAV was not extensively used in World War II [3].

Once the Cold War began in the 1960s the government sought a better way to collect intelligence. With advancements in stealth technology, the government created the U-2 spy plane to collect intelligence high above Soviet territory. However, once the U-2 was shot down in 1960, the government searched for a safer reconnaissance plane. The AQM-34 Ryan Firebee drone (see Fig. 1) was their answer to the problem. The Firebee UAV was one of the first jet propelled UAVs, and it can be considered the beginning of modern UAV technology. It was used extensively throughout the Vietnam War to gather intelligence, and a variant of the Firebee is still in operation in the Air Force and Navy today.

Fig. 1: The Ryan Firebee Dronehttp://upload.wikimedia.org/wikipedia/commons/3/3d/Teledyne-Ryan-Firebee-hatzerim-1.jpg

During the 1970s and 1980s the Israeli government aggressively developed UAVs, and many modern UAVs in the U.S. arsenal are based off of Israeli designs. With the help of the former chief designer for the Israeli Air Force, the U.S. developed the RQ-1 Predator in 1994 (see Fig. 2) [3]. Known for its extensive use in Iraq and Afghanistan, the Predator was first used exclusively for reconnaissance. However, due to its success, the government quickly expanded its work on UAVs to create the attack-variant MQ-1 Predator. In the past 15 years, the U.S. has continued its work on UAV technology and currently operates multiple types of both attack and reconnaissance UAVs. The most commonly used drones include the MQ-1 Predator, the more

powerful MQ-9 Reaper, the RQ-7 Global Hawk, and the RQ-170 Sentinel. Most recently the government has expanded research into smaller more versatile UAVs.

Fig. 2: The MQ-1 Predator UAVhttp://www.af.mil/shared/media/photodb/photos/081131-F-7734Q-001.jpg

Common Features in Modern UAVs

Modern UAVs come in many shapes and sizes, ranging from as small as a bird to as large as small planes. Until recently, most UAVs were similar in size and function to the MQ-1 Predator, but because of new advancements in UAVs, their design and features have become more varied. However, the most widely used military UAVs have many features in common, including similar propulsion systems, fuselage designs, optical systems, weapon systems, and control systems.

PropulsionModern UAVs utilize a wide variety of propulsion systems. Most commonly UAVs are propelled by a single or multiple propellers. The well known Predator uses a relatively simple Rotax 914 four cylinder 101-horsepower engine to power a variable-pitch propeller that is located in the rear of the plane [4]. The MQ-9 Reaper, the Predator's more powerful cousin, uses a turboprop engine to power its propeller, which allows it to reach speeds over 400 MPH or four times the speed of the Predator [5]. Other reconnaissance UAVs, like the RQ-7 Global Hawk, utilize jet engines to reach the high altitudes necessary to remain undetected. In recent years, the Air Force has expanded its use of rotor-powered UAVs. These UAVs can have one rotor like modern helicopters or multiple rotors, and they are typically smaller and more maneuverable than fixed-wing UAVs.

Fuselage DesignThe design of the fuselage in fixed-wing UAVs is similar across most UAVs. Since there is no need for a cockpit, the fuselage can be made into a simple aerodynamic shape. For this reason the design of the Predator has remained mostly unchanged for almost two decades. However,

recently the U.S. has experimented with more exotic designs. The classified Lockheed Martin RQ-170 Sentinel uses a long, single wing, similar in shape to the B-2 Bomber.

OpticsModern military UAVs use several different cameras and optical systems to control the plane and collect intelligence. The Predator uses a single camera attached to the nose of the plane for navigation. On the underside of the fuselage the plane is equipped with one variable aperture camera, one infrared camera for night operations, and a Synthetic Aperture Radar (SAR) that is capable of seeing through clouds and smoke. With these optical systems, the military is able to collect intelligence on enemy units from almost any altitude [4].

WeaponsOn the attack variant UAVs like the Predator and Reaper, the camera array is replaced with a Multiple Spectral Targeting System, or MTS. The MTS can fire a laser or infrared beam which is used to attract laser seeking missiles fired from the UAV or other vehicles. The Predator UAV can be equipped with two Hellfire missiles. These missiles can reach supersonic speeds, meaning the target will not be able to hear them coming.

ControlsUAVs are typically controlled using line-of-sight radio signals that are transmitted from a Ground Control Station (CGS). If the plane is not in the line of sight, the CGS can communicate with the UAV via a satellite link [4]. UAVs are also capable of completely autonomous flight using GPS coordinates as waypoints. Using GPS, UAVs can remain in completely autonomous flight for hours or even days without landing.

Military Applications

UAVs have many military applications. Traditionally they have been used to gather intelligence from high above the ground. In the past twenty years UAVs have assumed a more direct role in combat, capable of attacking targets with powerful missiles. More recently, the government has developed smaller UAVs that can be used by ground troops. Individual soldiers can use these micro-UAVs, or MAVs, to surveil nearby areas for enemy troops, allowing them to gather information from a safe distance. Commonly used MAVs are not dissimilar from civilian radio-controlled planes and helicopters equipped with one or multiple cameras.

Domestic/Commercial Applications

With the development of MAVs, UAV technology has become cheaper, easier to access, and easier to use. These developments have made it possible for UAVs to be used in every day applications. The applications for MAVs are nearly endless. Here are some of the ways UAVs are being used domestically by both government agencies and citizens alike.

Law Enforcement and Border Patrol

The Department of Homeland Security currently flies several Predators along the Mexican-American border. These unarmed drones aid in securing the border and can easily spot illegal immigrants using infrared cameras. In 2012, the agency locked-in to a five-year, $237 million deal with a California-based company to buy as many as 14 more UAVs for use in border protection [6]. Police departments across the country are also looking into the benefit of implementing small drones. In a few cases police have used MAVs to scout an area before sending officers [7]. While the benefits of MAVs in law enforcement are clear, few have been implemented due to privacy concerns [8].

Search and RescueUAVs and MAVs have large implications on how search and rescue missions will be carried out in the future. Small UAVs are ideal for searching for survivors in natural disasters. During the Hurricane Katrina aftermath, two UAVs were used to search for survivors. Rescuers used one fixed-wing UAV to quickly survey an area and one multi-rotor UAV to hover over buildings to provide additional help [9]. With further advances in autonomous flight, small UAVs may someday be able to autonomously search and relay the positions of survivors to rescuers.

Science ObservationsAs UAVs become cheaper and easier to use, they can be used to replace more expensive manned vehicles. In the field of science, UAVs can be used to make measurements of the atmosphere without the need for pilot. The National Oceanic and Atmospheric Administration, known as NOAA, uses a modified Global Hawk UAV to make measurements in the upper troposphere and lower stratosphere [10]. The long flight duration of the Global Hawk allows NOAA to take measurements over a longer period and wider range than would be possible with heavier piloted aircraft. UAVs also allow scientists to take measurements in areas too dangerous for pilots, such as within hurricanes or other severe weather.

Aerial PhotographyBecause of advances in high definition photography and video, even inexpensive MAVs can be used to take video and photos from previously inaccessible locations. With small high definition cameras and cheap radio-controlled MAVs (see Fig. 4), even amateur photographers can take high definition videos from virtually any angle and position. These types of UAVs make it possible to capture sporting events from new and interesting angles without the need for expensive equipment.

Fig. 3: The Draganflyer X4 Quadcopterhttp://www.draganfly.com/uav-helicopter/draganflyer-x4/gallery/pictures/picture-35.php

The Future of UAVs

As UAV technology progresses, more piloted aircraft will be replaced with cheaper and easier to operate UAVs. In the military, the government will no longer have to risk the lives of American pilots. In the future, smaller and more versatile MAVs have the potential to take ground troops off the front lines as well. UAVs have already been proven effective in military applications, and because of that UAV programs have expanded rapidly in the last decade. However, the possible applications for UAVs extends far beyond the military. In recent years, inexpensive yet extremely versatile UAVs and MAVs have become available to the public. The applications of these UAVs are nearly endless.

Quadrotor MAVsThe Quadrotor MAV is arguably the most versatile and easiest to use UAV that is publicly available. Its simple design consists of four rotors attached horizontally to a simple frame. The two pairs of rotors spin in opposite directions, effectively canceling out torque caused by each pair. By varying the speed of each rotor, the MAV can spin and tilt in any direction without the need for a vertical rotor like those used to stabilize traditional helicopters. The quadrotor can be controlled by amateur pilots, and is able to fly in any direction. Because quadrotors can be made into almost any size, they can be used for almost any application [11]. They can be easily programmed for autonomous flight, and thus may someday replace delivery services. A San Fancisco based company has already begun using a quadrotor to deliver tacos to customers

autonomously using GPS coordinates [12]. In the future, these simple UAVs may be buzzing everywhere above city skies.

Nano Air VehiclesResearch is currently being done by the Defense Advanced Research Projects Agency, or DARPA, to make current MAVs even smaller. These so-called Nano Air Vehicles, or NAVs, can be as small as a few centimeters and attempt to mimic the flight birds or insects. Based on specifications provided by DARPA, the Califonia-based company AeroVironment has created the Nano Hummingbird (Fig. 4). This small aircraft is designed to resemble a hummingbird in both flight and size. Equipped with small video camera, this tiny aircraft could be used to gather intelligence undetected in difficult to reach areas. DARPA is working to create even smaller NAVs, some as small as insects. These tiny aircraft open up possibilities for both the military and private sector alike. [1]

Fig. 4: The AeroVironment Nano Humingbird UAVhttp://www.nytimes.com/slideshow/2011/06/20/world/20110620-DRONES-8.html

Conclusion

UAVs started out strictly for military purposes, but with new publicly available UAVs and MAVs, their true potential is finally being realized. UAVs have already made the battlefield safer for pilots and soldiers, and they may someday completely eliminate the need to have

soldiers on the front lines. However, UAVs have far more applications in every day life. Since they are inexpensive and easy to control, MAVs like the quadrotor can be used for almost any purpose. People have already started using these UAVs in new and exciting ways, and as more people realize their potential, UAVs will no longer be thought of as remote killing machines. The applications of UAVs are nearly limitless. If the technology continues to progress as rapidly as it is now, UAVs will someday dominate the city skies, performing tasks not yet imagined.

References

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[2] L. Krock. "Timeline of UAVs". Nova. Available: http://www.pbs.org/wgbh/nova/spiesfly/uavs.html

[3] J. Garamone. (2002, Apr. 16). "From U.S. Civil War to Afghanistan: A Short History of UAVs." The U.S. Department of Defense. Available: http://www.defense.gov/news/newsarticle.aspx?id=44164

[4] R. Valdes. "How the Predator UAV Works." How Stuff Works. Available: http://science.howstuffworks.com/predator.htm

[5] "MQ-9 Reaper." U.S. Air Force. Available: http://www.af.mil/information/factsheets/factsheet.asp?id=6405

[6] J. Rosman. (2012, Nov. 19) "Border Patrol Locks in Multi-million Dollar Drone Contract." KPBS. Available: http://www.kpbs.org/news/2012/nov/19/border-patrol-multi-million-dollar-drone-contract/

[7] "The Dawning of Domestic Drones." (2012, Dec 25). New York Times. http://www.nytimes.com/2012/12/26/opinion/the-dawning-of-domestic-drones.html

[8] P. Finn. (2011, Jan. 23). "Domestic Use of Aerial Drones by Law Enforcement Likely to Prompt Privacy Debate." The Washington Post. Available: http://www.washingtonpost.com/wp-dyn/content/article/2011/01/22/AR2011012204111.html

[9] "Small, Unmanned Aircraft Search for Survivors in Katrina Wreckage." National Science Foundation. Available: http://www.nsf.gov/news/news_summ.jsp?cntn_id=104453

[10] A. Tuck et al. "The Global Hawk Tropical Troposphere Experiment." NOAA. Available: http://uas.noaa.gov/library/papers/GHATTEX_Proposal_Webversion_Jan2007.pdf

[11] J. Villbrandt. (2010, Jul. 1). "The Quadrotor's Coming of Age." Illumin. Available: http://illumin.usc.edu/162/the-quadrotors-coming-of-age/

[12] "Tacocopter Aims To Deliver Tacos Using Unmanned Drone Helicopters." (2012, Mar. 23). Huffington Post. Available: http://www.huffingtonpost.com/2012/03/23/tacocopter-startup-delivers-tacos-by-unmanned-drone-helicopter_n_1375842.html