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Looking for help for my thesis!


TAW_Blaze

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Hey guys!

 

I'm on university and got about a year till my graduation. I want to write my thesis about radars and I need someone with a lot of theoretical knowledge to help. The subject in short is creating a concept of multistatic pulse doppler radars to fight stealth. Obviously this cannot be done in this amount of time, I'm rather looking to start a research that I can continue later, while I can use parts of it to form my thesis.

 

If you know someone who is familiar with this stuff and is also willing to help, that would be really great. Thanks a lot!

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Unfortunately I can't really help you since I don't know anyone in the domain, but I am sincerely curious, is the idea to try to detect waves bounced off by the stealth plane at wavelengths way shorter than the plane scale, or to have an dispersed array of metric radars and try to rebuild an accurate picture using scattered fields?

[sIGPIC][/sIGPIC]

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The basic idea is that stealth by design reflects the least possible energy towards to direction of the incoming source. Basically we're looking at angular coverage of the target. There are a bunch of approaches I've seen mostly referred as bistatic radars that use this, albeit I haven't heard of any practical applications yet. Mine is quite different from those, well, so far anyway.

 

is the idea to try to detect waves bounced off by the stealth plane at wavelengths way shorter than the plane scale

 

Unfortunately I think this is impractical. Frequencies above ~ 15 GHz suffer from heavy atmospheric attenuation therefore it probably wouldn't work well in medium to long ranges.

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Sorry to answer a question with a question,

(& this is from an Anthropology major, not an engineer, so be less than scathing with your reply please :) )

.. but :

 

 

It's possible to achieve ultrasound transmission of sound using Parametric arrays to send two ultrasonic waves of differing frequencies toward a point, giving the illusion that the audible sound from their interference pattern was originating at that point (generate 'beats' at the virtual sound source through interference).

 

With a couple of EASA devices, would it not also be possible to do something similar through heterodyning - converge 2 tight beams of different frequencies at some small point in space, and have them interfere to create a virtual point source of longer & shorter wavelengths than the original beams - ones at which 'stealthy' planes radiate omnidirectionally, or are quite poorly stealthy and then move this virtual source in space until it ends up close enough to a stealthy plane to appreciably increase the strength of the signal you receive back (though the reflected LW half of the heterodyne pair's signals have poor angular resolution, the original generating VHF beams do not, so you still have a good spatial location for the target) ?

 

Analogy - I can't see a man in a dark coat on a dark night in the middle of a field from the farm gate if I just hold a candle by the gate, but if I get someone to carry the same candle out into the field and close to the man's face, I'll see his reflection perfectly well.

A powerful illumination source at the same location as the observer would do, but so will a weak (virtual) illumination source very close to the target.

If I can move the source through all space, eventually I'll find a direction from which the angle of reflection points at me...


Edited by Weta43

Cheers.

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It's possible to achieve ultrasound transmission of sound using Parametric arrays to send two ultrasonic waves of differing frequencies toward a point, giving the illusion that the audible sound from their interference pattern was originating at that point (generate 'beats' at the virtual sound source through interference).

 

So in short, you can "combine" 2 ultrasonic waves to create a virtual source at the point of convergence, and it'll "radiate" what comes from the interference. Still not sure if I got it right though..

 

With a couple of EASA devices, would it not also be possible to do something similar through heterodyning - converge 2 tight beams of different frequencies at some small point in space, and have them interfere to create a virtual point source of longer & shorter wavelengths than the original beams - ones at which 'stealthy' planes radiate omnidirectionally, or are quite poorly stealthy

 

With the typical frequency band fighters use I'm not sure if we can create higher wavelength through interference. And even if we could, it's extremely tough if not impossible to predict how they interfere. Datalink doesn't provide accurate enough information to properly and reliably line up the waves in specific phases.

 

and then move this virtual source in space until it ends up close enough to a stealthy plane to appreciably increase the strength of the signal you receive back (though the reflected LW half of the heterodyne pair's signals have poor angular resolution, the original generating VHF beams do not, so you still have a good spatial location for the target) ?

 

So you basically want to move around the point of convergence to gain angular resolution, and then somehow use the reflections from the virtual source of interfering signals. I like the idea, but to be honest I think it's a bit too overly complicated.

 

So far the plan is to converge narrow beams at a point of space. The main problem I have to solve is how to add up signals of different frequency constructively. GG told me that I should look into how STAP works, that will probably help. How much, we'll see. :)

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