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Photonic Radar
Photonic radar is a technique by which radar may be produced and analysed with the help of photonics rather than traditional RF engineering techniques. The frequency of the radar is still in the RF, but lasers are used to create and analyse the RF signals with high precision. China, Russia and India have active research programs to equip fighter aircraft with photonic radar. The potential benefits are longer range of detection, better position sensing, and 3D model target reconstruction. In one study, a test device could resolve objects as small as 3 x 4 cm (1.2 x 1.6 in), much smaller than traditional radar. Overview of operation A laser diode is used to generate an optical signal that is modulated by a linearly-chirped low frequency signal. This modulated optical signal is then split, with one part immediately converted to an electronic signal at 4 times the frequency of the original modulating signal. This waveform is then amplified, emitted via a standard antenna, and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photonics
Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in the form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Even though photonics is a commonly used term, there is no widespread agreement on a clear definition of the term or on the difference between photonics and related fields, such as optics. Photonics is closely related to quantum electronics, where quantum electronics deals with the theoretical part of it while photonics deal with its engineering applications. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term ''photonics'' developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s. History The word 'Photonics' is derived from the Greek w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RF Engineering
Radio-frequency (RF) engineering is a subset of electrical engineering involving the application of transmission line, Waveguide (electromagnetism), waveguide, Antenna (radio), antenna, radar, and Electromagnetic radiation, electromagnetic field principles to the design and application of devices that produce or use signals within the radio band, the frequency range of about 20 Hertz#SI multiples, kHz up to 300 Hertz#SI multiples, GHz. It is incorporated into almost everything that transmits or receives a radio wave, which includes, but is not limited to, mobile phones, radios, Wi-Fi, and two-way radios. RF engineering is a highly specialized field that typically includes the following areas of expertise: # Design of antenna systems to provide radiative coverage of a specified geographical area by an electromagnetic field or to provide specified sensitivity to an electromagnetic field impinging on the antenna. # Design of coupling and transmission line structures to tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after India, representing 17.4% of the world population. China spans the equivalent of five time zones and Borders of China, borders fourteen countries by land across an area of nearly , making it the list of countries and dependencies by area, third-largest country by land area. The country is divided into 33 Province-level divisions of China, province-level divisions: 22 provinces of China, provinces, 5 autonomous regions of China, autonomous regions, 4 direct-administered municipalities of China, municipalities, and 2 semi-autonomous special administrative regions. Beijing is the country's capital, while Shanghai is List of cities in China by population, its most populous city by urban area and largest financial center. Considered one of six ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders of Russia, land borders with fourteen countries. Russia is the List of European countries by population, most populous country in Europe and the List of countries and dependencies by population, ninth-most populous country in the world. It is a Urbanization by sovereign state, highly urbanised country, with sixteen of its urban areas having more than 1 million inhabitants. Moscow, the List of metropolitan areas in Europe, most populous metropolitan area in Europe, is the capital and List of cities and towns in Russia by population, largest city of Russia, while Saint Petersburg is its second-largest city and Society and culture in Saint Petersburg, cultural centre. Human settlement on the territory of modern Russia dates back to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since 2023; and, since its independence in 1947, the world's most populous democracy. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the north; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is near Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago., "Y-Chromosome and Mt-DNA data support the colonization of South Asia by modern humans originating in Africa. ... Coalescence dates for most non-European populations averag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fighter Aircraft
Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domination of the airspace above a battlefield permits bombers and attack aircraft to engage in tactical bombing, tactical and strategic bombing of enemy targets, and helps prevent the enemy from doing the same. The key performance features of a fighter include not only its firepower but also its high speed and maneuverability relative to the target aircraft. The success or failure of a combatant's efforts to gain air superiority hinges on several factors including the skill of its pilots, the tactical soundness of its doctrine for deploying its fighters, and the numbers and performance of those fighters. Many modern fighter aircraft also have secondary capabilities such as ground-attack aircraft, ground attack and some types, such as fighter-b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Diode
file:Laser diode chip.jpg, The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create active laser medium, lasing conditions at the diode's p–n junction, junction. Driven by voltage, the doped p–n-transition allows for carrier generation and recombination, recombination of an electron with a electron hole, hole. Due to the drop of the electron from a higher energy level to a lower one, radiation is generated in the form of an emitted photon. This is spontaneous emission. Stimulated emission can be produced when the process is continued and further generates light with the same phase, coherence, and wavelength. The choice of the semiconductor material determines the wavelength of the emitted beam, which in today's laser diodes range from the inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chirp
A chirp is a signal in which the frequency increases (''up-chirp'') or decreases (''down-chirp'') with time. In some sources, the term ''chirp'' is used interchangeably with sweep signal. It is commonly applied to sonar, radar, and laser systems, and to other applications, such as in spread-spectrum communications (see chirp spread spectrum). This signal type is biologically inspired and occurs as a phenomenon due to dispersion (a non-linear dependence between frequency and the propagation speed of the wave components). It is usually compensated for by using a matched filter, which can be part of the propagation channel. Depending on the specific performance measure, however, there are better techniques both for radar and communication. Since it was used in radar and space, it has been adopted also for communication standards. For automotive radar applications, it is usually called linear frequency modulated waveform (LFMW). In spread-spectrum usage, surface acoustic wave (S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog-to-digital Converter
In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a Digital signal (signal processing), digital signal. An ADC may also provide an isolated measurement such as an electronic device that converts an analog input voltage or Electric current, current to a digital number representing the magnitude of the voltage or current. Typically the digital output is a two's complement binary number that is proportional to the input, but there are other possibilities. There are several ADC hardware architecture, architectures. Due to the complexity and the need for precisely matched electronic component, components, all but the most specialized ADCs are implemented as integrated circuits (ICs). These typically take the form of metal–oxide–semiconductor (MOS) mixed-signal integrated circuit chips that integrate both Analogue electronics, anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Target Acquisition
Target acquisition is the detection and identification of the location of a target in sufficient detail to permit the effective employment of lethal and non-lethal means. The term is used for a broad area of applications. A "target" here is an entity or object considered for possible engagement or other action (see Targeting). Targets include a wide array of resources that an enemy commander can use to conduct operations including mobile and stationary units, forces, equipment, capabilities, facilities, persons and functions. It may comprise target acquisition, Joint Targeting or Information Operations. Technically target acquisition may just denote the process of a weapon system to decide which object to lock on to, as opposed to surveillance on one and target tracking on the other side; for example in an anti-aircraft system. History Target acquisition under the doctrines of the Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
