In general, detection is the action of accessing information without specific cooperation from with the sender.
108-468: In the history of radio communications, the term " detector " was first used for a device that detected the simple presence or absence of a radio signal , since all communications were in Morse code . The term is still in use today to describe a component that extracts a particular signal from all of the electromagnetic waves present. Detection is usually based on the frequency of the carrier signal , as in
216-460: A balloon carrier (the precursor to the aircraft carrier ) in the first offensive use of air power in naval aviation . Austrian forces besieging Venice attempted to launch some 200 incendiary balloons at the besieged city. The balloons were launched mainly from land; however, some were also launched from the Austrian ship SMS Vulcano . At least one bomb fell in the city; however, due to
324-471: A directional antenna transmits radio waves in a beam in a particular direction, or receives waves from only one direction. Radio waves travel at the speed of light in vacuum and at slightly lower velocity in air. The other types of electromagnetic waves besides radio waves, infrared , visible light , ultraviolet , X-rays and gamma rays , can also carry information and be used for communication. The wide use of radio waves for telecommunication
432-783: A drone , is an aircraft with no human pilot , crew, or passengers on board. 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. These include aerial photography , area coverage, precision agriculture , forest fire monitoring, river monitoring, environmental monitoring , policing and surveillance, infrastructure inspections, smuggling, product deliveries , entertainment, and drone racing . Many terms are used for aircraft which fly without any persons on board. The term drone has been used from
540-418: A microphone , a video signal representing moving images from a video camera , or a digital signal consisting of a sequence of bits representing binary data from a computer. The modulation signal is applied to a radio transmitter . In the transmitter, an electronic oscillator generates an alternating current oscillating at a radio frequency , called the carrier wave because it serves to generate
648-492: A radar screen . Doppler radar can measure a moving object's velocity, by measuring the change in frequency of the return radio waves due to the Doppler effect . Radar sets mainly use high frequencies in the microwave bands, because these frequencies create strong reflections from objects the size of vehicles and can be focused into narrow beams with compact antennas. Parabolic (dish) antennas are widely used. In most radars
756-521: A wave . They can be received by other antennas connected to a radio receiver ; this is the fundamental principle of radio communication. In addition to communication, radio is used for radar , radio navigation , remote control , remote sensing , and other applications. In radio communication , used in radio and television broadcasting , cell phones, two-way radios , wireless networking , and satellite communication , among numerous other uses, radio waves are used to carry information across space from
864-474: A " push to talk " button on their radio which switches off the receiver and switches on the transmitter. Or the radio link may be full duplex , a bidirectional link using two radio channels so both people can talk at the same time, as in a cell phone. One way, unidirectional radio transmission is called simplex . This is radio communication between a spacecraft and an Earth-based ground station, or another spacecraft. Communication with spacecraft involves
972-490: 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". UAV is a term that is commonly applied to military use cases. Missiles with warheads are generally not considered UAVs because the vehicle itself is a munition, but certain types of propeller-based missile are often called " kamikaze drones " by
1080-606: A Service Regulation specifying that "Radiotelegrams shall show in the preamble that the service is 'Radio ' ". The switch to radio in place of wireless took place slowly and unevenly in the English-speaking world. Lee de Forest helped popularize the new word in the United States—in early 1907, he founded the DeForest Radio Telephone Company, and his letter in the 22 June 1907 Electrical World about
1188-441: 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 systems , and can thus be built out of lighter but less sturdy materials and shapes, and can use less robustly tested electronic control systems. For small UAVs,
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#17328518041651296-574: A component of an unmanned aircraft system ( UAS ), which also includes a ground-based controller and a system of communications with the aircraft. The term UAS was adopted by the United States Department of Defense (DoD) and the United States Federal Aviation Administration (FAA) in 2005 according to their Unmanned Aircraft System Roadmap 2005–2030. The International Civil Aviation Organization (ICAO) and
1404-412: A controller device control the actions of a remote device. The existence of radio waves was first proven by German physicist Heinrich Hertz on 11 November 1886. In the mid-1890s, building on techniques physicists were using to study electromagnetic waves, Italian physicist Guglielmo Marconi developed the first apparatus for long-distance radio communication, sending a wireless Morse Code message to
1512-399: A detector such as a photodiode . In steganography , attempts to detect hidden signals in suspected carrier material is referred to as steganalysis . Steganalysis has an interesting difference from most other types of detection, in that it can often only determine the probability that a hidden message exists; this is in contrast to the detection of signals which are simply encrypted , as
1620-421: A given bandwidth than analog modulation , by using data compression algorithms, which reduce redundancy in the data to be sent, and more efficient modulation. Other reasons for the transition is that digital modulation has greater noise immunity than analog, digital signal processing chips have more power and flexibility than analog circuits, and a wide variety of types of information can be transmitted using
1728-545: A government license, such as the general radiotelephone operator license in the US, obtained by taking a test demonstrating adequate technical and legal knowledge of safe radio operation. Exceptions to the above rules allow the unlicensed operation by the public of low power short-range transmitters in consumer products such as cell phones, cordless phones , wireless devices , walkie-talkies , citizens band radios , wireless microphones , garage door openers , and baby monitors . In
1836-410: 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 aerial photography drone is an aircraft that has first-person video, autonomous capabilities, or both. An unmanned aerial vehicle ( UAV ) is defined as
1944-413: A human operator, as remotely piloted aircraft ( RPA ), or with various degrees of autonomy , such as autopilot assistance, up to fully autonomous aircraft that have no provision for human intervention. Based on the altitude, the following UAV classifications have been used at industry events such as ParcAberporth Unmanned Systems forum: An example of classification based on the composite criteria
2052-801: A human target in Libya , according to a report from the UN Security Council '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 Turkish Bayraktar TB2 , played a role in Azerbaijan's successes in the 2020 Nagorno-Karabakh war against Armenia. UAVs are also used in NASA missions. The Ingenuity helicopter
2160-572: A large economic cost, but it can also be life-threatening (for example, in the case of interference with emergency communications or air traffic control ). To prevent interference between different users, the emission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU), which allocates bands in the radio spectrum for different uses. Radio transmitters must be licensed by governments, under
2268-595: A metal conductor called an antenna . As they travel farther from the transmitting antenna, radio waves spread out so their signal strength ( intensity in watts per square meter) decreases (see Inverse-square law ), so radio transmissions can only be received within a limited range of the transmitter, the distance depending on the transmitter power, the antenna radiation pattern , receiver sensitivity, background noise level, and presence of obstructions between transmitter and receiver . An omnidirectional antenna transmits or receives radio waves in all directions, while
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#17328518041652376-427: A more limited information-carrying capacity and so work best with audio signals (speech and music), and the sound quality can be degraded by radio noise from natural and artificial sources. The shortwave bands have a greater potential range but are more subject to interference by distant stations and varying atmospheric conditions that affect reception. In the very high frequency band, greater than 30 megahertz,
2484-436: A parallel increase in the use of drones for consumer and general aviation activities. As of 2021, quadcopter drones exemplify the widespread popularity of hobby radio-controlled aircraft 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
2592-470: A primitive spark-gap transmitter . Experiments by Hertz and physicists Jagadish Chandra Bose , Oliver Lodge , Lord Rayleigh , and Augusto Righi , among others, showed that radio waves like light demonstrated reflection, refraction , diffraction , polarization , standing waves , and traveled at the same speed as light, confirming that both light and radio waves were electromagnetic waves, differing only in frequency. In 1895, Guglielmo Marconi developed
2700-420: A public audience. Analog audio is the earliest form of radio broadcast. AM broadcasting began around 1920. FM broadcasting was introduced in the late 1930s with improved fidelity . A broadcast radio receiver is called a radio . Most radios can receive both AM and FM. Television broadcasting is the transmission of moving images by radio, which consist of sequences of still images, which are displayed on
2808-459: A radio signal is usually concentrated in narrow frequency bands called sidebands ( SB ) just above and below the carrier frequency. The width in hertz of the frequency range that the radio signal occupies, the highest frequency minus the lowest frequency, is called its bandwidth ( BW ). For any given signal-to-noise ratio , an amount of bandwidth can carry the same amount of information ( data rate in bits per second) regardless of where in
2916-489: A receiver that is typically colocated with the transmitter. In radio navigation systems such as GPS and VOR , a mobile navigation instrument receives radio signals from multiple navigational radio beacons whose position is known, and by precisely measuring the arrival time of the radio waves the receiver can calculate its position on Earth. In wireless radio remote control devices like drones , garage door openers , and keyless entry systems , radio signals transmitted from
3024-521: A recipient over a kilometer away in 1895, and the first transatlantic signal on 12 December 1901. The first commercial radio broadcast was transmitted on 2 November 1920, when the live returns of the Harding-Cox presidential election were broadcast by Westinghouse Electric and Manufacturing Company in Pittsburgh, under the call sign KDKA . The emission of radio waves is regulated by law, coordinated by
3132-644: A reference to the radiotelegraph and radiotelegraphy . The use of radio as a standalone word dates back to at least 30 December 1904, when instructions issued by the British Post Office for transmitting telegrams specified that "The word 'Radio'... is sent in the Service Instructions." This practice was universally adopted, and the word "radio" introduced internationally, by the 1906 Berlin Radiotelegraphic Convention, which included
3240-446: A screen on a television receiver (a "television" or TV) along with a synchronized audio (sound) channel. Television ( video ) signals occupy a wider bandwidth than broadcast radio ( audio ) signals. Analog television , the original television technology, required 6 MHz, so the television frequency bands are divided into 6 MHz channels, now called "RF channels". The current television standard, introduced beginning in 2006,
3348-441: A smaller bandwidth than the old analog channels, saving scarce radio spectrum space. Therefore, each of the 6 MHz analog RF channels now carries up to 7 DTV channels – these are called "virtual channels". Digital television receivers have different behavior in the presence of poor reception or noise than analog television, called the " digital cliff " effect. Unlike analog television, in which increasingly poor reception causes
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3456-416: A television (video) signal has a greater data rate than an audio signal . The radio spectrum , the total range of radio frequencies that can be used for communication in a given area, is a limited resource. Each radio transmission occupies a portion of the total bandwidth available. Radio bandwidth is regarded as an economic good which has a monetary cost and is in increasing demand. In some parts of
3564-400: A transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft and missiles, a beam of radio waves emitted by a radar transmitter reflects off the target object, and the reflected waves reveal the object's location to
3672-652: A transmitter to control the actions of a device at a remote location. Remote control systems may also include telemetry channels in the other direction, used to transmit real-time information on the state of the device back to the control station. Uncrewed spacecraft are an example of remote-controlled machines, controlled by commands transmitted by satellite ground stations . Most handheld remote controls used to control consumer electronics products like televisions or DVD players actually operate by infrared light rather than radio waves, so are not examples of radio remote control. A security concern with remote control systems
3780-415: A variable payload are more likely to feature a distinct fuselage with a tail for stability, control and trim, although the wing configurations in use vary widely. For uses that require vertical flight or hovering, the tailless quadcopter requires a relatively simple control system and is common for smaller UAVs. Multirotor designs with 6 or more rotors is more common with larger UAVs, where redundancy
3888-435: A variety of license classes depending on use, and are restricted to certain frequencies and power levels. In some classes, such as radio and television broadcasting stations, the transmitter is given a unique identifier consisting of a string of letters and numbers called a call sign , which must be used in all transmissions. In order to adjust, maintain, or internally repair radiotelephone transmitters, individuals must hold
3996-413: Is amplified in the transmitter and applied to a transmitting antenna which radiates the energy as radio waves. The radio waves carry the information to the receiver location. At the receiver, the radio wave induces a tiny oscillating voltage in the receiving antenna which is a weaker replica of the current in the transmitting antenna. This voltage is applied to the radio receiver , which amplifies
4104-703: Is spoofing , in which an unauthorized person transmits an imitation of the control signal to take control of the device. Examples of radio remote control: Radio jamming is the deliberate radiation of radio signals designed to interfere with the reception of other radio signals. Jamming devices are called "signal suppressors" or "interference generators" or just jammers. During wartime, militaries use jamming to interfere with enemies' tactical radio communication. Since radio waves can pass beyond national borders, some totalitarian countries which practice censorship use jamming to prevent their citizens from listening to broadcasts from radio stations in other countries. Jamming
4212-512: Is U.S. Military's unmanned aerial systems (UAS) classification of UAVs based on weight, maximum altitude and speed of the UAV component. UAVs can be classified based on their power or energy source, which significantly impacts their flight duration, range, and environmental impact. The main categories include: The earliest recorded use of an unmanned aerial vehicle for warfighting occurred in July 1849, with
4320-445: Is a digital format called high-definition television (HDTV), which transmits pictures at higher resolution, typically 1080 pixels high by 1920 pixels wide, at a rate of 25 or 30 frames per second. Digital television (DTV) transmission systems, which replaced older analog television in a transition beginning in 2006, use image compression and high-efficiency digital modulation such as OFDM and 8VSB to transmit HDTV video within
4428-547: Is also less of a critical requirement for unmanned aircraft, allowing the designer greater freedom to experiment. Instead, UAVs are typically designed around their onboard payloads and their ground equipment. These factors have led to a great variety of airframe and motor configurations in UAVs. For conventional flight the flying wing and blended wing body offer light weight combined with low drag and stealth , and are popular configurations for many use cases. Larger types which carry
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4536-433: Is an audio transceiver , a receiver and transmitter in the same device, used for bidirectional person-to-person voice communication with other users with similar radios. An older term for this mode of communication is radiotelephony . The radio link may be half-duplex , as in a walkie-talkie , using a single radio channel in which only one radio can transmit at a time, so different users take turns talking, pressing
4644-468: Is an autonomous UAV that operated on Mars from 2021 to 2024. Current the Dragonfly spacecraft is being developed, and is aiming to reach and examine Saturn '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
4752-410: Is called "tuning". The oscillating radio signal from the desired station causes the tuned circuit to resonate , oscillate in sympathy, and it passes the signal on to the rest of the receiver. Radio signals at other frequencies are blocked by the tuned circuit and not passed on. A modulated radio wave, carrying an information signal, occupies a range of frequencies . The information ( modulation ) in
4860-427: Is called an uplink , while a link that transmits data from the spacecraft to the ground is called a downlink. Radar is a radiolocation method used to locate and track aircraft, spacecraft, missiles, ships, vehicles, and also to map weather patterns and terrain. A radar set consists of a transmitter and receiver. The transmitter emits a narrow beam of radio waves which is swept around the surrounding space. When
4968-458: Is estimated to take seven more years to reach the Saturnian system. Miniaturization is also supporting the development of small UAVs which can be used as individual system or in a fleet offering the possibility to survey large areas, in a relatively small amount of time. According to data from GlobalData , the global military uncrewed aerial systems (UAS) market, which forms a significant part of
5076-553: Is in radio clocks and watches, which include an automated receiver that periodically (usually weekly) receives and decodes the time signal and resets the watch's internal quartz clock to the correct time, thus allowing a small watch or desk clock to have the same accuracy as an atomic clock. Government time stations are declining in number because GPS satellites and the Internet Network Time Protocol (NTP) provide equally accurate time standards. A two-way radio
5184-417: Is mainly due to their desirable propagation properties stemming from their longer wavelength. In radio communication systems, information is carried across space using radio waves. At the sending end, the information to be sent is converted by some type of transducer to a time-varying electrical signal called the modulation signal. The modulation signal may be an audio signal representing sound from
5292-481: Is prioritized. Traditional internal combustion and jet engines 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
5400-524: Is the one-way transmission of information from a transmitter to receivers belonging to a public audience. Since the radio waves become weaker with distance, a broadcasting station can only be received within a limited distance of its transmitter. Systems that broadcast from satellites can generally be received over an entire country or continent. Older terrestrial radio and television are paid for by commercial advertising or governments. In subscription systems like satellite television and satellite radio
5508-564: Is usually accomplished by a powerful transmitter which generates noise on the same frequency as the target transmitter. US Federal law prohibits the nonmilitary operation or sale of any type of jamming devices, including ones that interfere with GPS, cellular, Wi-Fi and police radars. ELF 3 Hz/100 Mm 30 Hz/10 Mm SLF 30 Hz/10 Mm 300 Hz/1 Mm ULF 300 Hz/1 Mm 3 kHz/100 km Drone (aircraft) An unmanned aerial vehicle ( UAV ), or unmanned aircraft system ( UAS ), commonly known as
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#17328518041655616-521: 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 , but some carried armaments , such as the General Atomics MQ-1 Predator , that launched AGM-114 Hellfire air-to-ground missiles . CAPECON , a European Union project to develop UAVs, ran from 1 May 2002 to 31 December 2005. As of 2012 ,
5724-852: The Argus As 292 and the V-1 flying bomb with a jet engine . Fascist Italy developed a specialised drone version of the Savoia-Marchetti SM.79 flown by remote control, although the Armistice with Italy was enacted prior to any operational deployment. After World War II development continued in vehicles such as the American JB-4 (using television/radio-command guidance), the Australian GAF Jindivik and Teledyne Ryan Firebee I of 1951, while companies like Beechcraft offered their Model 1001 for
5832-705: 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. Similar terms are unmanned aircraft vehicle system ( UAVS ) and remotely piloted aircraft system ( RPAS ). Many similar terms are in use. Under new regulations which came into effect 1 June 2019,
5940-591: The International Telecommunication Union (ITU), which allocates frequency bands in the radio spectrum for various uses. The word radio is derived from the Latin word radius , meaning "spoke of a wheel, beam of light, ray". It was first applied to communications in 1881 when, at the suggestion of French scientist Ernest Mercadier [ fr ] , Alexander Graham Bell adopted radiophone (meaning "radiated sound") as an alternate name for his photophone optical transmission system. Following Hertz's discovery of
6048-552: The U.S. Navy in 1955. Nevertheless, they were little more than remote-controlled airplanes until the Vietnam War . In 1959, the U.S. Air Force , concerned about losing pilots over hostile territory, began planning for the use of uncrewed aircraft. Planning intensified after the Soviet Union 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
6156-575: The United States Air Force (USAF) employed 7,494 UAVs – almost one in three USAF aircraft. The Central Intelligence Agency 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. Due to their wide proliferation, no comprehensive list of UAV systems exists. The development of smart technologies and improved electrical-power systems led to
6264-503: The United States Department of Defense , UAVs are classified into five categories below: Other classifications of UAVs include: There are usually five categories when UAVs are classified by range and endurance: 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: Based on their weight, drones can be classified into 5 categories— . Drones could also be classified based on
6372-410: The ciphertext can often be identified with certainty, even if it cannot be decoded. In the military , detection refers to the special discipline of reconnaissance with the aim to recognize the presence of an object in a location or ambiance. Finally, the art of detection, also known as following clues , is the work of a detective in attempting to reconstruct a sequence of events by identifying
6480-456: The hydrogen fuel cell . 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
6588-497: The ionosphere without refraction , and at microwave frequencies the high-gain antennas needed to focus the radio energy into a narrow beam pointed at the receiver are small and take up a minimum of space in a satellite. Portions of the UHF , L , C , S , k u and k a band are allocated for space communication. A radio link that transmits data from the Earth's surface to a spacecraft
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#17328518041656696-401: The quadcopter 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 from crewed craft. For remote human control, a camera and video link almost always replace
6804-400: The radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten (10 ) metres, with corresponding frequency of 3 times a power of ten, and each covering a decade of frequency or wavelength. Each of these bands has a traditional name: It can be seen that the bandwidth , the range of frequencies, contained in each band is not equal but increases exponentially as
6912-459: The 1900s, and originally focused on providing practice targets for training military personnel . The earliest attempt at a powered UAV was A. M. Low 's "Aerial Target" in 1916. 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
7020-531: The 1920s with the introduction of broadcasting. Electromagnetic waves were predicted by James Clerk Maxwell in his 1873 theory of electromagnetism , now called Maxwell's equations , who proposed that a coupled oscillating electric field and magnetic field could travel through space as a wave, and proposed that light consisted of electromagnetic waves of short wavelength . On 11 November 1886, German physicist Heinrich Hertz , attempting to confirm Maxwell's theory, first observed radio waves he generated using
7128-601: 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
7236-618: The 1980s and 1990s, interest in UAVs grew within the higher echelons of the U.S. military. The U.S. funded the Counterterrorism Center (CTC) within the CIA, which sought to fight terrorism with the aid of modernized drone technology. In the 1990s, the U.S. DoD gave a contract to AAI Corporation 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
7344-540: The Atlantic Ocean on less than a gallon of fuel" holds this record. Besides the traditional piston engine, the Wankel rotary engine 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
7452-474: The Earth's atmosphere has less of an effect on the range of signals, and line-of-sight propagation becomes the principal mode. These higher frequencies permit the great bandwidth required for television broadcasting. Since natural and artificial noise sources are less present at these frequencies, high-quality audio transmission is possible, using frequency modulation . Radio broadcasting means transmission of audio (sound) to radio receivers belonging to
7560-589: The Middle East, Israeli intelligence tested the first tactical UAVs installed with reconnaissance 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 , Israel used UAVs as decoys to spur opposing forces into wasting expensive anti-aircraft missiles. After
7668-537: 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 . 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 described a fleet of uncrewed aerial combat vehicles in 1915. These developments also inspired
7776-472: The Syrian air defenses at the start of the 1982 Lebanon War , 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. With the maturing and miniaturization of applicable technologies in
7884-636: The Tonkin Gulf between naval units of the U.S. and the North Vietnamese Navy initiated America's highly classified UAVs ( Ryan Model 147 , Ryan AQM-91 Firefly , Lockheed D-21 ) into their first combat missions of the Vietnam War . 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 (1967–1970) in
7992-456: The UAV industry, is projected to experience a compound annual growth rate of 4.8% over the next decade. This represents a near doubling in market size, from $ 12.5 billion in 2024 to an estimated $ 20 billion by 2034. Crewed and uncrewed aircraft of the same type generally have recognizably similar physical components. The main exceptions are the cockpit and environmental control system or life support systems . Some UAVs carry payloads (such as
8100-580: The US, these fall under Part 15 of the Federal Communications Commission (FCC) regulations. Many of these devices use the ISM bands , a series of frequency bands throughout the radio spectrum reserved for unlicensed use. Although they can be operated without a license, like all radio equipment these devices generally must be type-approved before the sale. Below are some of the most important uses of radio, organized by function. Broadcasting
8208-503: The advances of computing technology, beginning with analog controls and evolving into microcontrollers, then system-on-a-chip (SOC) and single-board computers (SBC). Modern system hardware for UAV control 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
8316-405: The air simultaneously without interfering with each other because each transmitter's radio waves oscillate at a different rate, in other words, each transmitter has a different frequency , measured in hertz (Hz), kilohertz (kHz), megahertz (MHz) or gigahertz (GHz). The receiving antenna typically picks up the radio signals of many transmitters. The receiver uses tuned circuits to select
8424-414: The beam strikes a target object, radio waves are reflected back to the receiver. The direction of the beam reveals the object's location. Since radio waves travel at a constant speed close to the speed of light , by measuring the brief time delay between the outgoing pulse and the received "echo", the range to the target can be calculated. The targets are often displayed graphically on a map display called
8532-484: The cockpit windows; radio-transmitted digital commands replace physical cockpit controls. Autopilot software is used on both crewed and uncrewed aircraft, with varying feature sets. UAVs can be designed in different configurations than manned aircraft both because there is no need for a cockpit and its windows, and there is no need to optimize for human comfort, although some UAVs are adapted from piloted examples, or are designed for optionally piloted modes. Air safety
8640-665: The construction of the Kettering Bug by Charles Kettering from Dayton, Ohio and the Hewitt-Sperry Automatic Airplane – 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 invented a pilotless aerial torpedo that would explode at a preset time. The film star and model-airplane enthusiast Reginald Denny developed
8748-668: The continuous waves which were needed for audio modulation , so radio was used for person-to-person commercial, diplomatic and military text messaging. Starting around 1908 industrial countries built worldwide networks of powerful transoceanic transmitters to exchange telegram traffic between continents and communicate with their colonies and naval fleets. During World War I the development of continuous wave radio transmitters, rectifying electrolytic, and crystal radio receiver detectors enabled amplitude modulation (AM) radiotelephony to be achieved by Reginald Fessenden and others, allowing audio to be transmitted. On 2 November 1920,
8856-409: The control of a microcontroller unit (MCU). Flapping-wing ornithopters , 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. UAV computing capability followed
8964-466: The customer pays a monthly fee. In these systems, the radio signal is encrypted and can only be decrypted by the receiver, which is controlled by the company and can be deactivated if the customer does not pay. Broadcasting uses several parts of the radio spectrum, depending on the type of signals transmitted and the desired target audience. Longwave and medium wave signals can give reliable coverage of areas several hundred kilometers across, but have
9072-511: The degree of autonomy in their flight operations. ICAO classifies unmanned 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 manned or Optionally Piloted UAVs (OPVs). The flight of UAVs may operate under remote control by
9180-539: The early days of aviation , some being applied to remotely flown target aircraft used for practice firing of a battleship's guns, such as the 1920s Fairey Queen and 1930s de Havilland Queen Bee . Later examples included the Airspeed Queen Wasp and Miles Queen Martinet , before ultimate replacement by the GAF Jindivik . The term remains in common use. In addition to the software, autonomous drones also employ
9288-570: The existence of radio waves in 1886, the term Hertzian waves was initially used for this radiation. The first practical radio communication systems, developed by Marconi in 1894–1895, transmitted telegraph signals by radio waves, so radio communication was first called wireless telegraphy . Up until about 1910 the term wireless telegraphy also included a variety of other experimental systems for transmitting telegraph signals without wires, including electrostatic induction , electromagnetic induction and aquatic and earth conduction , so there
9396-404: The familiar frequencies of radio broadcasting , but it may also involve filtering a faint signal from noise , as in radio astronomy , or reconstructing a hidden signal, as in steganography . In optoelectronics , "detection" means converting a received optical input to an electrical output. For example, the light signal received through an optical fiber is converted to an electrical signal in
9504-413: The first commercial radio broadcast was transmitted by Westinghouse Electric and Manufacturing Company in Pittsburgh, under the call sign KDKA featuring live coverage of the Harding-Cox presidential election . Radio waves are radiated by electric charges undergoing acceleration . They are generated artificially by time-varying electric currents , consisting of electrons flowing back and forth in
9612-523: The first radio communication system, using a spark-gap transmitter to send Morse code over long distances. By December 1901, he had transmitted across the Atlantic Ocean. Marconi and Karl Ferdinand Braun shared the 1909 Nobel Prize in Physics "for their contributions to the development of wireless telegraphy". During radio's first two decades, called the radiotelegraphy era, the primitive radio transmitters could only transmit pulses of radio waves, not
9720-469: The first scaled remote piloted vehicle in 1935. Soviet researchers experimented with controlling Tupolev TB-1 bombers remotely in the late 1930s. In 1940, Denny started the Radioplane Company and more models emerged during World War II – used both to train antiaircraft gunners and to fly attack-missions. Nazi Germany produced and used various UAV aircraft during the war, like
9828-615: The frequency increases; each band contains ten times the bandwidth of the preceding band. The term "tremendously low frequency" (TLF) has been used for wavelengths from 1–3 Hz (300,000–100,000 km), though the term has not been defined by the ITU. The airwaves are a resource shared by many users. Two radio transmitters in the same area that attempt to transmit on the same frequency will interfere with each other, causing garbled reception, so neither transmission may be received clearly. Interference with radio transmissions can not only have
9936-402: The longest transmission distances of any radio links, up to billions of kilometers for interplanetary spacecraft . In order to receive the weak signals from distant spacecraft, satellite ground stations use large parabolic "dish" antennas up to 25 metres (82 ft) in diameter and extremely sensitive receivers. High frequencies in the microwave band are used, since microwaves pass through
10044-530: The loss rate is high, but we are willing to risk more of them ...they save lives!" During the 1973 Yom Kippur War , Soviet-supplied surface-to-air missile -batteries in Egypt and Syria caused heavy damage to Israeli fighter jets . As a result, Israel developed the IAI Scout as the first UAV with real-time surveillance. The images and radar decoys provided by these UAVs helped Israel to completely neutralize
10152-466: The need for legal restrictions warned that "Radio chaos will certainly be the result until such stringent regulation is enforced." The United States Navy would also play a role. Although its translation of the 1906 Berlin Convention used the terms wireless telegraph and wireless telegram , by 1912 it began to promote the use of radio instead. The term started to become preferred by the general public in
10260-505: The picture quality to gradually degrade, in digital television picture quality is not affected by poor reception until, at a certain point, the receiver stops working and the screen goes black. Government standard frequency and time signal services operate time radio stations which continuously broadcast extremely accurate time signals produced by atomic clocks , as a reference to synchronize other clocks. Examples are BPC , DCF77 , JJY , MSF , RTZ , TDF , WWV , and YVTO . One use
10368-456: The public and media. 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 unmanned flying craft as a UAV regardless of size. A similar term is remotely piloted aerial vehicle ( RPAV ). UAVs or RPAVs can also be seen as
10476-451: The radio frequency spectrum it is located, so bandwidth is a measure of information-carrying capacity . The bandwidth required by a radio transmission depends on the data rate of the information (modulation signal) being sent, and the spectral efficiency of the modulation method used; how much data it can transmit in each kilohertz of bandwidth. Different types of information signals carried by radio have different data rates. For example,
10584-409: The radio signal desired out of all the signals picked up by the antenna and reject the others. A tuned circuit (also called resonant circuit or tank circuit) acts like a resonator , similar to a tuning fork . It has a natural resonant frequency at which it oscillates. The resonant frequency of the receiver's tuned circuit is adjusted by the user to the frequency of the desired radio station; this
10692-451: The radio spectrum, the right to use a frequency band or even a single radio channel is bought and sold for millions of dollars. So there is an incentive to employ technology to minimize the bandwidth used by radio services. A slow transition from analog to digital radio transmission technologies began in the late 1990s. Part of the reason for this is that digital modulation can often transmit more information (a greater data rate) in
10800-456: The radio waves that carry the information through the air. The modulation signal is used to modulate the carrier, varying some aspect of the carrier wave, impressing the information in the modulation signal onto the carrier. Different radio systems use different modulation methods: Many other types of modulation are also used. In some types, a carrier wave is not transmitted but just one or both modulation sidebands . The modulated carrier
10908-405: The relevant information in a situation. Radio Radio is the technology of communicating using radio waves . Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates oscillating electrical energy, often characterized as
11016-481: The same digital modulation. Because it is a fixed resource which is in demand by an increasing number of users, the radio spectrum has become increasingly congested in recent decades, and the need to use it more effectively is driving many additional radio innovations such as trunked radio systems , spread spectrum (ultra-wideband) transmission, frequency reuse , dynamic spectrum management , frequency pooling, and cognitive radio . The ITU arbitrarily divides
11124-529: The term RPAS 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". UAVs may be classified like any other aircraft , according to design configuration such as weight or engine type, maximum flight altitude, degree of operational autonomy, operational role, etc. According to
11232-431: The transmitting antenna also serves as the receiving antenna; this is called a monostatic radar . A radar which uses separate transmitting and receiving antennas is called a bistatic radar . Radiolocation is a generic term covering a variety of techniques that use radio waves to find the location of objects, or for navigation. Radio remote control is the use of electronic control signals sent by radio waves from
11340-450: The war at a cost of about 554 UAVs lost to all causes. In the words of USAF General 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 , stated, "we let the drone do the high-risk flying ...
11448-510: The weak radio signal so it is stronger, then demodulates it, extracting the original modulation signal from the modulated carrier wave. The modulation signal is converted by a transducer back to a human-usable form: an audio signal is converted to sound waves by a loudspeaker or earphones, a video signal is converted to images by a display , while a digital signal is applied to a computer or microprocessor, which interacts with human users. The radio waves from many transmitters pass through
11556-522: 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 Quevedo introduced a radio-based control-system called the Telekino at the Paris Academy of Science in 1903, as a way of testing airships without risking human life. Significant development of drones started in
11664-585: Was a need for a more precise term referring exclusively to electromagnetic radiation. The French physicist Édouard Branly , who in 1890 developed the radio wave detecting coherer , called it in French a radio-conducteur . The radio- prefix was later used to form additional descriptive compound and hyphenated words, especially in Europe. For example, in early 1898 the British publication The Practical Engineer included
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