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Stealth and anti-stealth technology

Discussion in 'Indian Air Force' started by DrSomnath999, Jul 27, 2011.

  1. DrSomnath999

    DrSomnath999 Major RESEARCHER

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    Stealth technology

    Stealth technology has as its fundamental principle the prevention of detection by the enemy, and applies not only to aircraft as is commonly assumed, but also increasingly to naval vessels and to armored vehicles, although in the latter cases, it is nascent technology upon which comment must be reserved. Stealth technology, therefore, does not simply mean the evasion by aircraft of radar through the reduction of radar signature. It also encompasses the reduction of an aircraft's visibility in other spectra, most notably acoustic, visual, and infra-red. Consequently the popular term ‘stealth technology’ would perhaps be better referred to as ‘low-observable technology’.


    RADAR Stealth:
    RADAR is the use of reflected electromagnetic waves in the microwave part of the spectrum to detect targets or map landscapes. RADAR first illuminates the target, that is, transmits a radio pulse in its direction. If any of this energy is reflected by the target, some of it may be collected by a receiving antenna. By comparing the delay times for various echoes, information about the geometry of the target can be derived and, if necessary, formed into an image. RADAR stealth or invisibility requires that a craft absorb incident RADAR pulses, actively cancel them by emitting inverse waveforms, deflect them away from receiving antennas, or all of the above. Absorption and deflection, treated below, are the most important prerequisites of RADAR stealth.

    Absorption:
    Metallic surfaces reflect RADAR; therefore, stealth aircraft parts must either be coated with RADAR-absorbing materials or made out of them to begin with. The latter is preferable because an aircraft whose parts are intrinsically RADAR-absorbing derives aerodynamic as well as stealth function from them, whereas a RADAR-absorbent coating is, aerodynamically speaking, dead weight. The F-117 stealth aircraft is built mostly out of a RADAR-absorbent material termed Fibaloy, which consists of glass fibers embedded in plastic, and of carbon fibers, which are used mostly for hot spots like leading wing-edges and panels covering the jet engines. Thanks to the use of such materials, the airframe of the F-117 (i.e., the plane minus its electronic gear, weapons, and engines) is only about 10% metal. Both the B-2 stealth bomber and the F-117 reflect about as much RADAR as a hummingbird

    Deflection:
    Most Radar are monotonic, that is, for reception they use either the same antenna as for sending or a separate receiving antenna collocated with the sending antenna; deflection therefore
    means reflecting RADAR pulses in any direction other than the one they came from. This in turn requires that stealth aircraft lack flat, vertical surfaces that could act as simple RADAR mirrors. RADAR can also be strongly reflected wherever three planar surfaces meet at a corner. Planes such as the B-52 bomber, which have many flat, vertical surfaces and RADAR-reflecting corners, are notorious for their RADAR-reflecting abilities; stealth aircraft, in contrast, tend to be highly angled and streamlined, presenting no flat surfaces at all to an observer that is not directly above or below them. The B-2 bomber, for example, is shaped like a boomerang.

    Counter-stealth:
    An aircraft cannot be made truly invisible. For example, no matter how cool the exhaust vents of an aircraft are kept, the same amount of heat is always liberated by burning a given amount of fuel, and this heat must be left behind the aircraft as a trail of warm air. Infrared-detecting devices might be devised that could image this heat trail as it formed, tracking a stealth aircraft.
    Furthermore, every jet aircraft leaves swirls of air—vortices—in its wake. Doppler radar, which can image wind velocities, might pinpoint such disturbances if it could be made sufficiently high-resolution.
    Other anti-stealth techniques could include the detection of aircraft-caused disturbances in the Earth's magnetic field (magnetic anomaly detection), networks of low frequency radio links to detect stealth aircraft by interruptions in transmission, the use of specially shaped RADAR pulses that resist absorption, and netted RADAR. Netted RADAR is the use of more than one receiver, and possibly more than one transmitter, in a network. Since stealth aircraft rely partly on deflecting RADAR pulses, receivers located off the line of pulse transmission might be able to detected deflected echoes. By illuminating a target area using multiple transmitters and linking multiple receivers into a coordinated network, it should be possible to greatly increase one's chances of detecting a stealthy target. No single receiver may record a strong or steady echo from any single transmitter, but the network as a whole might collect enough information to track a stealth target.

    ANTI-STEALTH TECHNOLOGY
    Anti- stealth technology is based on the aim that a stealthy craft remain invisible to detecting radar and infrared sensors and that too especially at long ranges.

    These technologies can be entirely nullified as well, with the help of the detecting radar and/or infrared sensors searching. This works for searching the background behind the stealthy craft but not for the stealthy craft.

    After the detection the stealthy craft shows up in the form of a black or blank outlined figure in front of the background.

    This is very similar to the way the location of the moon can be pinpointed with extreme accuracy and the movement can be tracked with great precision during a solar eclipse, even when the moon cannot be observed itself in an eclipse.

    Basically the stealthy crafts use materials which absorb the radar waves or use pointed and flat designs to reflect the waves in different directions, away from the radar equipment.

    In respect of infrared the basic principle used is by minimizing the heat from the engines and other heat emitting spots thereby achieving the objective of stealth technology. This technology can be nullified entirely by the detecting radar and/or infrared sensors, which would search the background of the stealthy craft and not the craft itself.

    There are three Methods used till date for the anti-stealth technology:
    1.Airborne Method:

    • One successful way to accomplish the objective of the anti-stealth technology is by using SLAR (Side-Looking Airborne Radar) and/or FLIR (Front-Looking Infra-Red) equipment in a high-flying aircraft to map out the terrain below and to one side, or to the front.
    • If a stealth craft were operating anywhere above the terrain which is being mapped, a small patch of that terrain, where the stealth craft has been flying, would not be observed on the detecting aircraft's output screen. That portion/Spot will appear black or blank, like a silhouette of the stealth aircraft. Thereby pinpointing the position of the stealth craft in the field of vision and detecting it.
    • Initially the detection of the craft may be slow, since the detecting device may have to detect the whole of the terrain just to locate the stealth craft. But once the stealth craft is detected, it becomes very easy to track the craft and very swiftly and accurately by zooming in the exact location and some of the surrounding areas, the craft can be followed. This zooming in session would help the detecting equipment to generate more detailed information of the craft and probably the craft can be identified by the silhouette of the detected craft.

    2.Satellite-Based Method
    The Satellite method may also be used on battlefields by looking down from satellites equipped with radar sensors. Though satellites are comparatively far away from the battlefield, say about a couple of hundred miles away, or even more, they would not run much risk of being shot down as they would be able to remain out of range of most hostile weapons.

    Also, satellites would be able to cover a much larger area of the battlefield, thereby being in a position to locate and track virtually all hostile stealth craft.

    3. Surface-Based Method

    Another way for the detection of the stealth aircraft would be with the use of surface-based radar installations which scan the sky at high apertures and with high sensitivity, such as is done with radio telescopes. Since these detectors are surface-based, there large and heavy size would not actually matter as they'll be a surface set up. According to the radio astronomers, radio signals from the stars reach the radar surface set up installations even in daytime and bad weather conditions uninterrupted. The radio map of the stars is very well known now, it is assumed that if any star is not observed on the detecting screen or output device, that particular star must be eclipsed by some craft flying above the installation somewhere along the line of sight between the installation and that particular star. If more than one detecting installation were used, the exact location in three dimensions of all aircraft friendly as well as hostile within the fields of vision of the relevant installations could be determined by a process of triangulation, with great accuracy.


    REFERENCES:
    • WWW.STEALTH.EDU.COM
    • WWW.ANTI-STEALTH.COM
     
    INDIAN NATIONALIST likes this.
  2. satya

    satya Lieutenant FULL MEMBER

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    the rat-cat race....... no true winner
     
  3. DrSomnath999

    DrSomnath999 Major RESEARCHER

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    well the chinese & russian are seriously developing anti stealth weapons like russian have developed TAMARA anti stealth radar,SA -20 sams
     
  4. DrSomnath999

    DrSomnath999 Major RESEARCHER

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    who will be loser in this race wont be alive for 2nd chance
     
    kiduva21 likes this.
  5. midgetman

    midgetman 2nd Lieutant FULL MEMBER

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    i don't believe an anti stealth system exists... yet..
     
  6. Jungibaaz

    Jungibaaz Lt. Colonel ELITE MEMBER

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    no such thing as stealth to begin with matey.

    I do believe there are simple but effective ways of dealing with VLO objects.
    High powered AESA, advanced datalinks (combining same radar signatures from different sources to provide you a overall clearer picture).
    For now.... Stealth is the way forward.
     
  7. Mr_Breaker

    Mr_Breaker Lieutenant FULL MEMBER

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  8. Averageamerican

    Averageamerican Colonel ELITE MEMBER

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    US stealth was built because it was realized long ago that their would be dramatic increases in both the detection ability of antiaircraft systems and the accuracy of air to air and ground to air missiles. Moores law on the increase efficiency of electronics made it fact of life. That being said the USA has been concentrating on stealth for several generations of planes with the game plan that the most stealthy plane with the longest range air to air and ground to air missiles is going to be the victor 95 percent of the time. In any kind of warfare if you know where the enemy is before he knows where you are you have a tremendous advantage. Any thing else is just wishful thinking.
     
  9. halloweene

    halloweene Major MILITARY STRATEGIST

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    Btw, ONERA is having a passive FLYING radar prototype in tests...
     
    Picdelamirand-oil likes this.

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