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YLC-4 Radar
YLC-4 is a Chinese UHF solid-state, fully coherent 2D long range surveillance radar, which is mainly used for long range surveillance. The radar has the ability to synthesize data from up to four other radars with a large data capacity, and to communicate and display the data and state of the system through the net to realize remote control and detection. When equipped with height-finding radar, it can perform the function of guidance and providing target data for an air traffic control system. With long range detection range, high reliability and easy maintenance, YLC-4 radar is a main radar in air defense network. The manufacturer of the system is Nanjing Research Institute of Electronics Technology (NRIET)/Nanjing Institute No. 1 /南京电子技术研究所. Design The YLC-4 system consist of four components: the antenna, the signal cabin, transmitter and the power generators (2 x 120 kW diesel generators). Specifications *Frequency range: P band Microwave is a form of ... [...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] |
Surveillance
Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing, or directing. This can include observation from a distance by means of electronic equipment, such as closed-circuit television (CCTV), or interception of electronically transmitted information like Internet traffic. Increasingly, Government, governments may also obtain Customer data, consumer data through the purchase of online information, effectively expanding surveillance capabilities through commercially available digital records. It can also include simple technical methods, such as Human intelligence (intelligence gathering), human intelligence gathering and postal interception. Surveillance is used by citizens, for instance for protecting their neighborhoods. It is widely used by governments for intelligence gathering, including espionage, prevention of crime, the protection of a process, person, group or object, or the investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Traffic Control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC is to prevent collisions, organise and expedite the flow of traffic in the air, and provide information and other support for pilots. Personnel of air traffic control monitor aircraft location in their assigned airspace by radar and communicate with the pilots by radio. To prevent collisions, ATC enforces Separation (air traffic control), traffic separation rules, which ensure each aircraft maintains a minimum amount of 'empty space' around it at all times. It is also common for ATC to provide services to all General aviation, private, Military aviation, military, and commercial aircraft operating within its airspace; not just civilian aircraft. Depending on the type of flight and the class of airspace, AT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P Band
Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequencies between 300 MHz and 300 GHz, broadly construed. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 30 cm and 3 mm), or between 1 and 3000 GHz (30 cm and 0.1 mm). In all cases, microwaves include the entire super high frequency (SHF) band (3 to 30 GHz, or 10 to 1 cm) at minimum. The boundaries between far infrared, terahertz radiation, microwaves, and ultra-high-frequency (UHF) are fairly arbitrary and differ between different fields of study. The prefix ' in ''microwave'' indicates that microwaves are small (having shorter wavelengths), compared to the radio waves used in prior radio technology. Frequencies in the microwave range are often referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 that affect the calculation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant False Alarm Rate
Constant false alarm rate (CFAR) detection is a common form of adaptive algorithm used in radar systems to detect target returns against a background of noise, clutter and interference. Principle In the radar receiver, the returning echoes are typically received by the antenna, amplified, down-converted to an intermediate frequency, and then passed through detector circuitry that extracts the envelope of the signal, known as the ''video signal''. This video signal is proportional to the power of the received echo. It comprises the desired echo signal as well as the unwanted signals from internal receiver noise and external clutter and interference. The term ''video'' refers to the resulting signal being appropriate for display on a cathode ray tube, or "video screen". The role of the constant false alarm rate circuitry is to determine the power threshold above which any return can be considered to probably originate from a target as opposed to one of the spurious sources. If ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosecant Squared Antenna
A cosecant squared antenna, sometimes known as a constant height pattern, is a modified form of parabolic reflector used in some radar systems. It is shaped to send more radio energy in certain directions in order to smooth out the reception pattern of objects as their range changes in relation to the radar. The name refers to the fact that the amount of energy returned from a target drops off with the square of the cosecant of the angle between the radar and the target. Development The concept originated as part of the development of the H2S radar, which scanned the area under an aircraft to provide a radar map of the ground below. The ground directly below the aircraft is at a distance equal to the aircraft's altitude and produces the strongest signal. The terrain return at further distances is much a weaker signal due to the radar equation. The slant range distance between the radar and the terrain is the cosecant of the angle between the fuselage and the target, and the ener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Radars
Ground may refer to: Geology * Land, the solid terrestrial surface of the Earth * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical circuit from which voltages are measured * Earthing system, part of an electrical installation that connects with the Earth's conductive surface * Ground and neutral, closely related terms Law * Ground (often grounds), in law, a rational motive or basis for a belief, conviction, or action taken, such as a legal action or argument: * Grounds for divorce, regulations specifying the circumstances under which a person will be granted a divorce Music * ''Ground'' (album), the second album by the Nels Cline Trio * "Ground" (song), one of the songs in the debut album of the Filipino rock band Rivermaya * Ground bass, in music, a bass part that continually repeats, while the melody and harmony over it change * '' The Ground'', a 2005 album by Norwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
