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25-786: [REDACTED] Look up LPI in Wiktionary, the free dictionary. LPI may refer to: Places [ edit ] Linköping/Saab Airport (IATA code), Sweden Linus Pauling Institute , at Oregon State University, US Pyramide Inversée , a skylight constructed in an underground shopping mall in front of the Louvre Museum in France Lady Parry Island , an uninhabited island in Nunavut, Canada Organizations [ edit ] Lunar and Planetary Institute ,

50-774: A benchmarking tool created by the World Bank Limited Price Indexation , a pricing index used in the calculation of increases in certain components of scheme pension payments in the UK Legatum Prosperity Index , an annual ranking developed by the Legatum Institute Other uses [ edit ] La Paz incident , occurred in May 1863 at the ghost town of La Paz in Confederate Arizona and

75-405: A benchmarking tool created by the World Bank Limited Price Indexation , a pricing index used in the calculation of increases in certain components of scheme pension payments in the UK Legatum Prosperity Index , an annual ranking developed by the Legatum Institute Other uses [ edit ] La Paz incident , occurred in May 1863 at the ghost town of La Paz in Confederate Arizona and

100-513: A large volume of space for targets, it is likely that the main lobe will repeatedly be pointing at the RWR. Modern phased-array radars not only control their side lobes , they also use very thin, fast-moving beams of energy in complicated search patterns. This technique may be enough to confuse the RWR so it does not recognize the radar as a threat, even if the signal itself is detected. In addition to stealth considerations, reducing side and back lobes

125-689: A measure of plant leaf age based on morphological development Lysophosphatidylinositol , an endocannabinoid neurotransmitter Living Planet Index , an indicator of the state of global biological diversity, based on trends in vertebrate populations of species from around the world Lines per inch , a measurement of printing resolution Laser Peripheral Iridotomy; See Glaucoma surgery Liquid phase injectors and liquid propane injection, in autogas Low-power idle in Energy-Efficient Ethernet Economics and finance [ edit ] Logistics Performance Index ,

150-598: A measure of plant leaf age based on morphological development Lysophosphatidylinositol , an endocannabinoid neurotransmitter Living Planet Index , an indicator of the state of global biological diversity, based on trends in vertebrate populations of species from around the world Lines per inch , a measurement of printing resolution Laser Peripheral Iridotomy; See Glaucoma surgery Liquid phase injectors and liquid propane injection, in autogas Low-power idle in Energy-Efficient Ethernet Economics and finance [ edit ] Logistics Performance Index ,

175-426: A method of making decisions based on insufficient or fuzzy information See also [ edit ] Low probability of intercept radar (LPIR), a radar system designed to be difficult to detect Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title LPI . If an internal link led you here, you may wish to change the link to point directly to

200-426: A method of making decisions based on insufficient or fuzzy information See also [ edit ] Low probability of intercept radar (LPIR), a radar system designed to be difficult to detect Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title LPI . If an internal link led you here, you may wish to change the link to point directly to

225-456: A rotating antenna, or similar passive array using phase or amplitude comparison . Typically RWRs store the detected pulses for a short period of time, and compare their broadcast frequency and pulse repetition frequency against a database of known radars. The direction to the source is normally combined with symbology indicating the likely purpose of the radar – Airborne early warning and control , surface-to-air missile , etc. This technique

250-758: A scientific research institute dedicated to study of the solar system, its formation, evolution, and current state Linux Professional Institute , a non-profit organization that provides vendor-independent professional certification for Linux system administrators and programmers LPI Media , a gay and lesbian publisher in the United States Science and technology [ edit ] Dye penetrant inspection or liquid penetrant inspection, an inspection method used to locate surface-breaking defects in all non-porous materials Lysinuric protein intolerance , an autosomal recessive metabolic disorder affecting amino acid transport Leaf plastochron index ,

275-685: A scientific research institute dedicated to study of the solar system, its formation, evolution, and current state Linux Professional Institute , a non-profit organization that provides vendor-independent professional certification for Linux system administrators and programmers LPI Media , a gay and lesbian publisher in the United States Science and technology [ edit ] Dye penetrant inspection or liquid penetrant inspection, an inspection method used to locate surface-breaking defects in all non-porous materials Lysinuric protein intolerance , an autosomal recessive metabolic disorder affecting amino acid transport Leaf plastochron index ,

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300-451: A signal and then listening for its echo off distant objects. Each of these paths, to and from the target, is subject to the inverse square law of propagation in both the transmitted signal and the signal reflected back. That means that a radar's received energy drops with the fourth power of the distance, which is why radar systems require high powers, often in the megawatt range, to be effective at long range. The radar signal being sent out

325-410: Is a simple radio signal, and can be received with a simple radio receiver . Military aircraft and ships have defensive receivers, called radar warning receivers (RWR), which detect when an enemy radar beam is on them, thus revealing the position of the enemy. Unlike the radar unit, which must send the pulse out and then receive its reflection, the target's receiver does not need the reflection and thus

350-420: Is common on ships, for instance. Unlike the radar, which knows in which direction it is sending its signal, the receiver simply gets a pulse of energy and has to interpret it. Since the radio spectrum is filled with noise, the receiver's signal is integrated over a short period of time, making periodic sources like a radar add up and stand out over the random background. The rough direction can be calculated using

375-495: Is desirable as it makes the radar more difficult to characterise. This can increase the difficulty in determining which type it is (concealing information about the carrying platform) and make it much harder to jam . Systems that feature LPIR include modern active electronically scanned array (AESA) radars such as that on the F/A-18E/F Super Hornet and the passive electronically scanned array (PESA) radar on

400-466: Is much less useful against a radar with a frequency-agile (solid state) transmitter. Agile radars like AESA (or PESA ) can change their frequency with every pulse (except when using doppler filtering), and generally do so using a random sequence, integrating over time does not help pull the signal out of the background noise. Moreover, a radar may be designed to extend the duration of the pulse and lower its peak power. An AESA or modern PESA will often have

425-449: Is why AESAs are also known as "low probability of intercept radars". Modern RWRs must be made highly sensitive (small angles and bandwidths for individual antennas, low transmission loss and noise) and add successive pulses through time-frequency processing to achieve useful detection rates. Ways of reducing the profile of a radar include using wider bandwidth ( wideband , Ultra-wideband ), frequency hopping , using FMCW , and using only

450-480: The capability to alter these parameters during operation. This makes no difference to the total energy reflected by the target but makes the detection of the pulse by an RWR system less likely. Nor does the AESA have any sort of fixed pulse repetition frequency, which can also be varied and thus hide any periodic brightening across the entire spectrum. Older generation RWRs are essentially useless against AESA radars, which

475-443: The free dictionary. LPI may refer to: Places [ edit ] Linköping/Saab Airport (IATA code), Sweden Linus Pauling Institute , at Oregon State University, US Pyramide Inversée , a skylight constructed in an underground shopping mall in front of the Louvre Museum in France Lady Parry Island , an uninhabited island in Nunavut, Canada Organizations [ edit ] Lunar and Planetary Institute ,

500-406: The intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=LPI&oldid=1165177994 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages LPI [REDACTED] Look up LPI in Wiktionary,

525-405: The intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=LPI&oldid=1165177994 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Low probability of intercept radar LPI measures include: Radar systems work by sending out

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550-399: The minimum power required for the task. Using pulse compression also reduces the probability of detection, since the peak transmitted power is lower while the range and resolution is the same. Constructing a radar so as to emit minimal side and back lobes may also reduce the probability of interception when it is not pointing at the radar warning receiver. However, when the radar is sweeping

575-477: The signal drops off only as the square of distance. This means that the receiver is always at an advantage [neglecting disparity in antenna size] over the radar in terms of range - it will always be able to detect the signal long before the radar can see the target's echo. Since the position of the radar is extremely useful information in an attack on that platform, this means that radars generally must be turned off for lengthy periods if they are subject to attack; this

600-653: Was the westernmost confrontation of the American Civil War Language Proficiency Index , a Canadian standardized test for English proficiency written and administered by the University of British Columbia Applied Research and Evaluation Services Leading pedestrian interval , a type of traffic control Licensed private investigator, a type of private investigator Liga Primer Indonesia , an Indonesian top-tier football league held in 2011 Linear partial information ,

625-489: Was the westernmost confrontation of the American Civil War Language Proficiency Index , a Canadian standardized test for English proficiency written and administered by the University of British Columbia Applied Research and Evaluation Services Leading pedestrian interval , a type of traffic control Licensed private investigator, a type of private investigator Liga Primer Indonesia , an Indonesian top-tier football league held in 2011 Linear partial information ,

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