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Thread: Radar to detect stealth planes

  1. #1 Radar to detect stealth planes 
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    I have a feeling the governments of the world are researching it behind closed doors.

    Is anyone publicly aware of research being done into new types of "radar" or something completely different that will reflect off a aircraft with stealth technology

    I also understand that stealth doesn't make something invisible on radar just very very small cross section

    what about a super sensitive radar (that could detect stealth planes and birds or whatever else is that small) then use computers to differentiate between them to identify the planes

    plane flies at mach 3 at 50,000 ft for example

    Just wanted to hear thoughts on this


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    I don't know what the military are working on for new radar systems but you nailed a couple of the problems with radar pretty well.
    NATO used to have a problem with the cars on the roads near the East European and West European countries during the cold war era. They had to fly patrols ready to intercept any planes approaching the USSR's border. Note it was not to intercept small planes coming from USSR but from the NATO side.
    The problem was if they set the radar to detect anything moving below 100 kph it would snow out from all the automobile traffic on the road. Any planes travelling slower than that were lost in the noise anyhow so they tuned the radar to detect only things which were faster. This made anything flying slower than the speed of a transport truck invisible to them. USSR had the same problem and the same solution.




    In 1987 Mathias Rust flew a Cessna from Finland to Moscow and landed it in Red Square. It seems Rust was a bit of a nutcase but because of the failures in the USSR defence system it is worth reading up on it. It was a huge embarrassment for Soviet air defence and qualified as an "international incident."


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  4. #3  
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    Do you think a computer could solve the snowed out effect to determine which of the objects were cars and which were threats
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    Possibly now you could but not back then.
    In 1988 the most advanced radar systems available were on the ship USS Vincennes. It had extremely sensitive radar with the best computer systems available to identify and track targets. The Vincennes managed to shoot down an Iranian passenger jet thinking it was a jet fighter.
    The Iranian passenger jet was #655. It was another hugely embarrassing international incident, and again well worth reading about.
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  6. #5  
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    Quote Originally Posted by Always.Asking View Post
    I have a feeling the governments of the world are researching it behind closed doors.
    And publishing such work in open-source publications.

    Is anyone publicly aware of research being done into new types of "radar" or something completely different that will reflect off a aircraft with stealth technology
    Yes, I'm aware of such "research" 1 PLUS it's not that necessary.
    Stealth is configured to deflect/ absorb/ reduce signatures at particular wavelengths.
    Change the radar type (wavelength) and your aircraft suddenly isn't stealthy as such.

    what about a super sensitive radar (that could detect stealth planes and birds or whatever else is that small) then use computers to differentiate between them to identify the planes
    plane flies at mach 3 at 50,000 ft for example
    Considering that there's damn' few aircraft that CAN fly at such speeds and altitudes that one is a no-brainer.
    But: IF it's a stealth type then by the time it's close enough to actually return a distinguishable signal it's already too late to intercept it. Regardless of what computing power is assigned to the task.

    Stealth reduces the range at which a target can be be picked up and identified: adding computing power won't affect that in any significant manner.

    1 For example the (Chinese-led?) method of "looking at gaps" in TV signal transmissions, and bi-static radars.
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  7. #6  
    Forum Radioactive Isotope cosmictraveler's Avatar
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    I understand that Doppler radar will "see" raindrops so why can't It detect stealth planes.?
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  8. #7  
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    Quote Originally Posted by cosmictraveler View Post
    I understand that Doppler radar will "see" raindrops so why can't It detect stealth planes.?
    Um, not quite true.
    Doppler radar is a "class" of radar (i.e. the way it operates and takes "measurements" - it detects motion relative to a datum - in the case of military doppler that datum is the ground: it filters out anything not covering ground at speed 2).
    The one you've mentioned is
    A) at a non-military frequency (my take on it - it's referred to as "high resolution" 1).
    B) limited in utility for the military: narrow 0.22 degree beamwidth and a [search] volume about the size of a small bus (roughly 14 m3) when operating at a range of 2 km. (I.e. very short range 3 and a "ridiculously" small (militarily useless) search volume).
    Plus, of course, even if it were of a range and volume capability to be of use for the military all that would mean is that the enemy select their design criteria to deflect/ absorb that particular wavelength.
    It's a swings and roundabouts game.

    1 Presumably not what the military mean by that term - it's a limited application research radar.
    2 So much so that if the target aircraft flies at 90 degrees to the searching aircraft it "disappears" from a doppler radar - zero motion realtive to the ground along line-of-flight of the searching aircraft.
    3 2 km is a waste of time for a search radar: BVR (Beyond Visual Range) combat is classed as anything OVER 5 miles (8 km). At 2 km even if it COULD pick up [any and all] stealth aircraft chances are that the pilot of the searching fighter would have seen the target with the original Mk.1 eyeball that is standard issue for all pilots.
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  9. #8  
    Forum Radioactive Isotope cosmictraveler's Avatar
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    Thanks again.
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  10. #9  
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    High speed targets would likely be missiles instead of planes.
    Drones have smaller radar signatures than stealth planes do.
    Stealth radar is being developed.

    Radar Research Can Track High Speed Targets, Missiles | Archive of News Releases | College of Engineering | UTEP
    UTEP Engineering Professor Dr. Benjamin Flores is performing cutting edge research that promises to make the country a safer place.For more than a decade, Flores has done extensive research on radar. Funded by the Department of Defense and the Office of Naval Research, his research has led him to develop new radar signal processing approaches to obtain images of targets such as military aircraft or even intercontinental, ballistic missiles coming in through the atmosphere at high speeds.
    The speeds at which these objects travel challenge current radar technology. Flores’ research involves the use of microwaves to get a clear, focused picture of airborne targets. It can easily tell the difference between friend and foe and provides numerous other details such as size, shape and even the type of propulsion engines.
    According to Flores, ballistic missiles undergo significant stress upon re-entry into the atmosphere. Information obtained from radar images can be used to determine whether the missiles are intact, have deployed multiple warheads, or have been destroyed.
    “These images provide accurate information that can be used to make smart decisions,” said Flores. “For instance mobilizing intercepting fighters can be an expensive proposition when a target is detected. Modern radar technology can be used to decide whether to just watch the target, or to send a fighter. So the approach is also cost effective.”
    There are other advantages. By disguising radar waves as microwave noise, the technology becomes virtually undetectable. No one else would know that the target is being tracked.
    “If an air craft is not responding to radio, we can use this technology to monitor them,” said Flores. “It may be a simple radio malfunction, but there is still a need to monitor it. This technology will track and continuously monitor the target. It is ideal for the next generations of airport surveillance systems.”
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  11. #10  
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    Quote Originally Posted by dan hunter View Post
    STEALTHY Drones have smaller radar signatures than stealth planes do.
    Just to be picky.
    Radar signature isn't necessarily dependent on physical size: in fact the smaller a vehicle is the more likely it is to approximate a half-wavelength of the radar that's looking for it - and THAT will give a larger return.
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  12. #11  
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    Quote Originally Posted by Dywyddyr View Post
    Just to be picky.
    Radar signature isn't necessarily dependent on physical size: in fact the smaller a vehicle is the more likely it is to approximate a half-wavelength of the radar that's looking for it - and THAT will give a larger return.
    Why do you assume a shorter object would be more likely to match the 1/2 lambda?
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  13. #12  
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    Quote Originally Posted by dan hunter View Post
    Why do you assume a shorter object would be more likely to match the 1/2 lambda?
    Let's try again:
    Quote Originally Posted by Dywyddyr View Post
    in fact the smaller a vehicle is the more likely it is to approximate a half-wavelength of the radar
    Current wavelengths are well sub-metre.
    Ergo a small drone is MORE LIKELY to approach half a wave length in some dimensions than is a full-size manned aircraft.
    It's not actually my claim: Bill Gunston's book Warplanes of the Future (Octopus Books) states exactly that.
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  14. #13  
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    Quote Originally Posted by cosmictraveler View Post
    I understand that Doppler radar will "see" raindrops so why can't It detect stealth planes.?
    The most common wavelength weather radar is 10 cm for both non-Doppler and Doppler. It can't see individual raindrops but can see groups of raindrops (as well as bugs, raised dust clouds, as well as snow, hail etc). Some weather researchers do use much shorter wavelength radars for cloud studies.
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  15. #14  
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by dan hunter View Post
    Why do you assume a shorter object would be more likely to match the 1/2 lambda?
    Let's try again:
    Quote Originally Posted by Dywyddyr View Post
    in fact the smaller a vehicle is the more likely it is to approximate a half-wavelength of the radar
    Current wavelengths are well sub-metre.
    Ergo a small drone is MORE LIKELY to approach half a wave length in some dimensions than is a full-size manned aircraft.
    It's not actually my claim: Bill Gunston's book Warplanes of the Future (Octopus Books) states exactly that.
    Are you sure Mr Gunston got it right?
    If the wavelength is much less than the object size (like microwaves are) then the object reflects the wave from its surface and resonance does not play much of a role. Because it is reflecting from the surface instead of by resonationg area is much more important.
    At least that is what my understanding of it is.

    If you look at the stealth aircraft you will see very sharp edges facing likely radar sources and sloping surfaces to reflect the radar past the plane instead of back to the source.
    You will also see that black paint with all those small metal balls in it to break up reflections too.

    Air defence radar is usually in the S band which is about 10cm.
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  16. #15  
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    Quote Originally Posted by dan hunter View Post
    Are you sure Mr Gunston got it right?
    Well he was (before he died) one of the world's leading aviation authors/ experts 1.
    And consulted by many people in the field.

    If the wavelength is much less than the object size...
    ...it doesn't fall into the category of the object approximating half a wavelength. We're not, so far, fielding sub-millimetre drones.

    If you look at the stealth aircraft you will see very sharp edges facing likely radar sources and sloping surfaces to reflect the radar past the plane instead of back to the source.
    You will also see that black paint with all those small metal balls in it to break up reflections too.
    Um, okay. The point?

    Air defence radar is usually in the S band which is about 10cm.
    The S band is used by weather radar, surface ship radar, and some communications satellites. 7.5–15 cm.
    D- Band (L-Band Radar) This frequency band (1 to 2 GHz) is preferred for the operation of long-range air-surveillance radars. 15–30 cm.


    1 But his Russian pronunciation was terrible.
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  17. #16  
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    How are Mie scattering and Rayliegh scattering different and what difference does it make to radar target detection?
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    Hmm, the diagram didn't copy properly.
    Green = Rayleigh, pink - Mie, blue = optical.

    Radar Basics - Rayleigh- versus Mie- Scattering and Optical Region
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  19. #18  
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    That is OK, I couldn't get the viewgrams from the IEEE free course to post properly either. They lose their formatting for some reason.

    Can you relate it to radar frequency choice and the range of the radar system for me?
    I am not having an easy time understanding the lectures.
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  20. #19  
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    Dy...do you think the F-35 will be the last of the man-piloted aircraft? (fighter aircraft at least)
    Fixin' shit that ain't broke.
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    Quote Originally Posted by MacGyver1968 View Post
    Dy...do you think the F-35 will be the last of the man-piloted aircraft? (fighter aircraft at least)
    Fighters yes for the developed world.
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  22. #21  
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    Quote Originally Posted by MacGyver1968 View Post
    Dy...do you think the F-35 will be the last of the man-piloted aircraft? (fighter aircraft at least)
    You're forgetting the PAK-FA (Sukhoi T-50) and/ or the Chinese J-20 etc?
    The F-35 is more of an attack aircraft than a fighter as such (despite the glowing press) 1.

    1 I told LM 15 (20?) years ago that it would be crap, and it's managed to exceed even my "expectations".
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