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Low-probability-of-intercept Radar
A low-probability-of-intercept radar (LPIR) is a radar employing measures to avoid detection by passive radar detection equipment (such as a radar warning receiver (RWR), or electronic support receiver) while it is passive radar#Target detection, searching for a target or engaged in passive radar#Line tracking, target tracking. This characteristic is desirable in a radar because it allows finding and tracking an opponent without alerting them to the radar's presence. This also protects the radar installation from anti-radiation missiles (ARMs). LPI measures include: *Power management and high duty cycle, meaning the transmitter is on most of the time (long integration times) *Wide bandwidth (or Ultra-wideband) *Frequency agility, and frequency selection *Advanced/irregular scan patterns *Coded pulses (coherent detection) *High processing gain *Low sidelobe antennas Rationale Radar systems work by sending out a signal and then listening for its echo off distant objects. Each of 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] |
Passive Electronically Scanned Array
A passive electronically scanned array (PESA), also known as passive phased array, is an antenna in which the beam of radio waves can be electronically steered to point in different directions (that is, a phased array antenna), in which all the antenna elements are connected to a single transmitter (such as a magnetron, a klystron or a travelling wave tube) and/or receiver. The largest use of phased arrays is in radars. Most phased array radars in the world are PESA. The civilian microwave landing system uses PESA transmit-only arrays. A PESA contrasts with an active electronically scanned array (AESA) antenna, which has a separate transmitter and/or receiver unit for each antenna element, all controlled by a computer; AESA is a more advanced, sophisticated versatile second-generation version of the original PESA phased array technology. Hybrids of the two can also be found, consisting of subarrays that individually resemble PESAs, where each subarray has its own RF front e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northrop Grumman
Northrop Grumman Corporation is an American multinational Aerospace manufacturer, aerospace and Arms industry, defense company. With 97,000 employees and an annual revenue in excess of $40 billion, it is one of the world's largest Arms industry, weapons manufacturers and military technology providers. Formed in 1994 through Northrop Corporation's purchase of Grumman Aerospace, Northrop Grumman ranked as the List of defense contractors, third-largest defense contractor in the world as of 2022. The firm ranked on the 2022 Fortune 500, ''Fortune'' 500 list of America's largest corporations. Northrop Grumman and its industry partners have won the Collier Trophy nine times, most recently for the development and production of the James Webb Space Telescope, an Space telescope, orbiting observatory launched in 2021. Northrop Grumman leads the development of the Northrop Grumman B-21 Raider, B-21 Raider, a long-range, stealth aircraft, stealth strategic bomber that can drop conv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AN/APG-77
The AN/APG-77 is a multifunction low probability of intercept radar installed on the F-22 Raptor fighter aircraft. The radar was designed and initially built by Westinghouse and Texas Instruments, and production continued with their respective successors Northrop Grumman and Raytheon after acquisition. It is a solid-state, active electronically scanned array (AESA) radar. Composed of 1,956 transmit/receive modules (TRM), each about the size of a gum stick, it can perform a near-instantaneous beam steering (in the order of tens of nanoseconds). In accordance with the Joint Electronics Type Designation System (JETDS), the "''AN/APG-77''" designation represents the 77th design of an Army-Navy airborne electronic device for radar fire-control equipment. The JETDS system also now is used to name all Department of Defense electronic systems. The APG-77 was highly appreciated by pilots transitioning from F-15s upon the F-22's introduction in 2005, providing a massive boost in situa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SA-10 Grumble
The S-300 (NATO reporting name SA-10 Grumble) is a series of long-range surface-to-air missile systems developed by the former Soviet Union. It was produced by NPO Almaz for the Soviet Air Defence Forces to defend against air raids and cruise missiles. It is used by Russia, Ukraine, and other former Eastern Bloc countries, along with Bulgaria and Greece. It is also used by China, Iran, and other countries in Asia. The system is fully automated, though manual observation and operation are also possible. Each targeting radar provides target designation for the central command post. The command post compares the data received from the targeting radars and filters out false targets. The central command post has both active and passive target detection modes. Missiles have a maximum range of from the command post. The successor to the S-300 is the S-400 (NATO reporting name ''SA-21 Growler''), which entered service on 28 April 2007. Variations and upgrades There are currentl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passive Electronically Scanned Array
A passive electronically scanned array (PESA), also known as passive phased array, is an antenna in which the beam of radio waves can be electronically steered to point in different directions (that is, a phased array antenna), in which all the antenna elements are connected to a single transmitter (such as a magnetron, a klystron or a travelling wave tube) and/or receiver. The largest use of phased arrays is in radars. Most phased array radars in the world are PESA. The civilian microwave landing system uses PESA transmit-only arrays. A PESA contrasts with an active electronically scanned array (AESA) antenna, which has a separate transmitter and/or receiver unit for each antenna element, all controlled by a computer; AESA is a more advanced, sophisticated versatile second-generation version of the original PESA phased array technology. Hybrids of the two can also be found, consisting of subarrays that individually resemble PESAs, where each subarray has its own RF front e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F/A-18E/F Super Hornet
The Boeing F/A-18E and F/A-18F Super Hornet are a series of American supersonic twinjet, twin-engine, Carrier-based aircraft, carrier-capable, Multirole combat aircraft, multirole fighter aircraft derived from the McDonnell Douglas F/A-18 Hornet. The Super Hornet is in service with the armed forces of the United States, Australia, and Kuwait. The F/A-18E single-seat and F tandem-seat variants are larger and more advanced versions of the F/A-18C and D Hornet, respectively. A strike fighter capable of air-to-air and air-to-ground/surface missions, the Super Hornet has an internal 20mm M61 Vulcan, M61A2 rotary cannon and can carry air-to-air missiles, air-to-surface missiles, and a variety of other weapons. Additional fuel can be carried in up to five external fuel tanks and the aircraft can be configured as an airborne tanker by adding an external Aerial refueling, air-to-air refueling system. Designed and initially produced by McDonnell Douglas, the Super Hornet first flew in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Electronically Scanned Array
An active electronically scanned array (AESA) is a type of phased array antenna, which is a computer-controlled antenna array in which the beam of radio waves can be electronically steered to point in different directions without moving the antenna. In the AESA, each antenna element is connected to a small solid-state transmit/receive module (TRM) under the control of a computer, which performs the functions of a transmitter and/or receiver for the antenna. This contrasts with a passive electronically scanned array (PESA), in which all the antenna elements are connected to a single transmitter and/or receiver through phase shifters under the control of the computer. AESA's main use is in radar, and these are known as active phased-array radar (APAR). The AESA is a more advanced, sophisticated, second-generation of the original PESA phased-array technology. PESAs can only emit a single beam of radio waves at a single frequency at a time. The PESA must utilize a Butler matri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Jamming And Deception
Radar jamming and deception is a form of electronic countermeasures (ECMs) that intentionally sends out radio frequency signals to interfere with the operation of radar by saturating its receiver with noise or false information. Concepts that blanket the radar with signals so its display cannot be read are normally known as jamming, while systems that produce confusing or contradictory signals are known as deception, but it is also common for all such systems to be referred to as jamming. There are two general classes of radar jamming, mechanical and electronic. Mechanical jamming entails reflecting enemy radio signals in various ways to provide false or misleading target signals to the radar operator. Electronic jamming works by transmitting additional radio signals towards enemy receivers, making it difficult to detect real target signals, or take advantage of known behaviors of automated systems like radar lock-on to confuse the system. Various Electronic counter-countermeasur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Side Lobe
In antenna engineering, sidelobes are the lobes (local maxima) of the far field radiation pattern of an antenna or other radiation source, that are not the ''main lobe''. The radiation pattern of most antennas shows a pattern of "''lobes''" at various angles, directions where the radiated signal strength reaches a maximum, separated by "''nulls''", angles at which the radiated signal strength falls to zero. This can be viewed as the diffraction pattern of the antenna. In a directional antenna in which the objective is to emit the radio waves in one direction, the lobe in that direction is designed to have a larger field strength than the others; this is the "''main lobe''". The other lobes are called "''sidelobes''", and usually represent unwanted radiation in undesired directions. The sidelobe directly behind the main lobe is called the back lobe. The longer the antenna relative to the radio wavelength, the more lobes its radiation pattern has. In transmitting antennas, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phased-array
In antenna theory, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving the antennas. In a phased array, the power from the transmitter is fed to the radiating elements through devices called ''phase shifters'', controlled by a computer system, which can alter the phase or signal delay electronically, thus steering the beam of radio waves to a different direction. Since the size of an antenna array must extend many wavelengths to achieve the high gain needed for narrow beamwidth, phased arrays are mainly practical at the high frequency end of the radio spectrum, in the UHF and microwave bands, in which the operating wavelengths are conveniently small. Phased arrays were originally invented for use in military radar systems, to detect fast moving planes and missiles, but are now widely used and have spread to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Compression
Pulse compression is a signal processing technique commonly used by radar, sonar and Ultrasound, echography to either increase the range angular resolution, resolution when pulse length is constrained or increase the Signal-to-noise ratio, signal to noise ratio when the peak power and the Bandwidth_(signal_processing), bandwidth (or equivalently range resolution) of the transmitted signal are constrained. This is achieved by modulation, modulating the transmitted pulse and then Cross-correlation, correlating the received signal with the transmitted pulse. Simple pulse Signal description The ideal model for the simplest, and historically first type of signals a pulse radar or sonar can transmit is a truncated sinusoidal pulse (also called a CW --carrier wave-- pulse), of amplitude A and carrier frequency, f_0, truncated by a rectangular function of width, T. The pulse is transmitted periodically, but that is not the main topic of this article; we will consider only a single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
