|
Normalized Radar Cross Section
Radar cross-section (RCS), denoted σ, also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. An object reflects a limited amount of radar energy back to the source. The factors that influence this include: *the material with which the target is made; *the size of the target relative to the wavelength of the illuminating radar signal; *the absolute size of the target; *the angle of incidence (optics), incident angle (angle at which the radar beam hits a particular portion of the target, which depends upon the shape of the target and its orientation to the radar source); *the reflected angle (angle at which the reflected beam leaves the part of the target hit; it depends upon incident angle); *the polarization of the radiation transmitted and received with respect to the orientation of the target. While important in detecting targets, strength of emitter and distance are not factors t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Cross Section Of Metal Sphere From Mie Theory
Radar is a system that uses radio waves to determine the distance (''ranging''), direction (geometry), 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, Marine radar, ships, spacecraft, guided missiles, motor vehicles, map Weather radar, weather formations, and terrain-following radar, terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym and initialism, acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an wikt:anacronym, anacronym, a common noun, Acronym#All-caps style, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio spectrum, radio or microwave domain, a transmitting antenna (radio), antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a radio receiver, receiver an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaff (countermeasure)
Chaff, originally called Window or Düppel, is a radar countermeasure involving the dispersal of thin strips of aluminium, metallized glass fiber, or plastic. Dispersed chaff produces a large radar cross section intended to blind or disrupt radar systems. Modern military forces use chaff to distract active radar homing missiles from their targets. Military aircraft and warships can be equipped with chaff dispensing systems for self-defense. During its midcourse phase, an intercontinental ballistic missile may release chaff along with its other penetration aids. Contemporary radar systems can distinguish chaff from legitimate targets by measuring the Doppler effect; chaff quickly loses speed after leaving an aircraft, and the resulting shift in wavelength of the radar return can be measured. To counter this, a chaff cloud can be illuminated by the defending vehicle with a doppler-corrected frequency. This is known as JAFF (jammer plus chaff) or CHILL (chaff-illuminated). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface-to-air-missile
A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground or the sea to destroy aircraft or other missiles. It is one type of anti-aircraft system; in modern armed forces, missiles have replaced most other forms of dedicated anti-aircraft weapons, with anti-aircraft guns pushed into specialized roles. The first attempt at SAM development took place during World War II, but no operational systems were introduced. Further development in the 1940s and 1950s led to operational systems being introduced by most major forces during the second half of the 1950s. Smaller systems, suitable for close-range work, evolved through the 1960s and 1970s, to modern systems that are man-portable. Shipborne systems followed the evolution of land-based models, starting with long-range weapons and steadily evolving toward smaller designs to provide a layered defence. This evolution of desig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lockheed F-117 Nighthawk
The Lockheed F-117 Nighthawk is an officially retired American single-seat, subsonic, twin-engined, stealth attack aircraft developed by Lockheed's secretive Skunk Works division and operated by the United States Air Force (USAF). It was the first operational aircraft to be designed with stealth technology. Work on what would become the F-117 commenced in the 1970s as a means of countering increasingly sophisticated Soviet surface-to-air missiles (SAMs). During 1976, the Defense Advanced Research Projects Agency (DARPA) issued Lockheed a contract to produce the '' Have Blue'' technology demonstrator, the test data from which validated the concept. On 1 November 1978, Lockheed decided to proceed with the F-117 development program. Five prototypes were produced; the first of which performed its maiden flight in 1981 at Groom Lake, Nevada. The first production F-117 was delivered in 1982, and its initial operating capability was achieved in October 1983. All aircraft were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
