Chengdu J-20 5th Generation Aircraft News & Discussions

[telephone]

whats the top speed on this plane?

 

[gambit]

If you hadn't been spamming my posts with b.s. rhetoric, I would have explained it.

You make me unhappy. I ignore you.

There are three critical differences. You can figure it out yourself.

I doubt that you can explain the basics of resonance behaviors. Actually, I explained it a long time ago before you got here. But clue for you, complex bodies degrades resonance behaviors.

There are 2 planes in the world with EODAS. That'd be the J-20 and F-35; the PAK-FA still uses a single IRST camera ball. These provide full 3-D situational awareness in the IR spectrum. If the J-20's electronics are not at the level of F-35, then it is at least 2nd best. Payload and high range influence survivability due to being able to strategically deploy the aircraft at airfields further away from places where they are more likely to be destroyed by a preemptive attack and to place more buffer radars/IADS so that they can perform at maximum efficiency. In addition, it reduces the constraints of fuel on maneuvering. High payload influences survivability by giving the plane more opportunities to shoot down other planes before being forced to retreat.

That is not survivability, which is about the ability to avoid physical threats and/or survive them WHILE being in a hostile environment, not out of it.

 

[amalakas]

I doubt that you can explain the basics of resonance behaviors. Actually, I explained it a long time ago before you got here. But clue for you, complex bodies degrades resonance behaviors.


That is not survivability, which is about the ability to avoid physical threats and/or survive them WHILE being in a hostile environment, not out of it.

I think you must have heard wrong Gambit, or must have served in a naive service like me (no wonder since we follow your doctrine mostly)

survivability is not what you think apparently, neither is what air forces demand on paper when the issue letters of interest on particular requirements. They just need bigger tanks on the planes.

And apparently, the stupid russians who cannot produce a stealth plane, can produce L band radars (ground nonetheless) that can track an F-22 class body.

and moreover you can triangulate using them to find A single F-22!!

all I say is WOW.

let me summarise

: proper use of term survivability thrown to garbage
: understanding of what role L -band ground radars play, thrown to garbage
: Stealth design of the F-22, thrown to garbage because of statistical mean and resonance

need I go on?

 

[gambit]

: Stealth design of the F-22, thrown to garbage because of statistical mean and resonance

Here is a Chinese source and a clue to our Chinese friend who thinks that the resonance effect can be so simple to create and model...

An Error Occurred Setting Your User Cookie

The complex natural resonances (poles) of complex radar targets are usually extracted from measured signature, and have low precision because of being extremely sensitive to noise. In numerically methods to calculate targets' poles, the method of moment (MoM) combined with contour integration is a smart one and widely used. But that method is limited to simple shaped or revolution objects. For complex shaped targets by that method, the number of poles in contour is incorrectly estimated, and the results are inaccurate.

There are no shortages of publicly available information on how as complex a body as an aircraft compared to a blimp or the simple sphere can screw up what was originally believed to be simple by overwhelming said complex body with wavelengths that matches or larger than target dimensions.

Another example...

ScienceDirect.com - AEU - International Journal of Electronics and Communications - Extraction of electromagnetic target poles from multiple scattered fields with damped Min-norm method

In this study, the estimation of complex natural resonance frequencies (target poles) by using damped minimum-norm (DMin-norm) method is presented. The method mainly utilizes from the scattered fields belonging to multiple aspect angle/polarization cases of a target in resonance scattering region. By employing DMin-norm algorithm, the proposed method constitutes a function from which target poles can be efficiently extracted as its roots. However, the method in its conventional form should be executed as many times as the number of scattered fields to collect sufficient number of resonance frequencies. Therefore, the method is further improved in terms of computational time to acquire target poles with a single process for multiple scattered data. The described method is applied to a dielectric sphere having high number of target poles and good agreement between estimated and theoretical poles is observed.

Complex bodies create multiple interruptions during the travel time and distance of the impinging wave and each scattering point is called a 'pole'.

Another example...

CHARACTERIZATION OF PERFECTLY CONDUCTING TARGETS IN RESONANCE DOMAIN WITH THEIR QUALITY OF RESONANCE

J. Chauveau, N. de Beaucoudrey, and J. Saillard

Institut de Recherche en Electrotechnique
et Electronique de Nantes Atlantique (IREENA)
Universit´ de Nantese
Polytech’Nantes, rue Christian Pauc, BP50609
44306 Nantes Cedex 03, France

Abstract—In resonance domain, the radar scattering response of any object can be modelled by natural poles of resonance with the formalism of the Singularity Expansion Method. The mapping of these poles in the complex plane gives useful information for the discrimination of a radar target, as its general shape, its characteristic dimension and its constitution. In this paper, we use an analogy with resonant circuits modelling to define the quality factor Q of each resonance. Therefore, we propose to characterize the resonance behavior of perfectly conducting targets with this quality factor Q and the natural pulsation of resonance ω0 . Indeed, this new representation in {ω0 ; Q} allows to better separate information than the usual mapping of natural poles of resonance in the complex plane. For perfectly conducting canonical and complex shape targets, we present results exhibiting advantages of these two parameters {ω0 ; Q}.

1. INTRODUCTION

For years, the Singularity Expansion Method (SEM) has been used to characterize the electromagnetic response of structures in both the time and the frequency domains. SEM was first introduced by Baum [1, 2] and was inspired by observing that typical transient temporal responses of various scatterers (e.g. aircrafts, antennas, ...) behave as a combination of exponentially damped sinusoids. Such damped sinusoids correspond, in the complex frequency domain, to complex conjugate poles called natural poles of resonance.

How to compensate for these disturbances is not to eliminate them from calculations but to increase the complexity of the algorithms and it all returned to the simple sphere and the 10-lambda rule,which our man omitted from his 'discussion' because he does not understand how all these things integrate.

That undulation is because of the signal continually wrapping itself around the sphere IF its wavelength is greater than sphere/cylinder diameter, aka the '10-lambda' rule. As the wavelength/diameter ratio increases that undulation disappear because the electrical path (diameter) is too great and signal loss via 'leaky waves' eliminate that 'wrapping' around effect.

Which lead us to this point...

The SR-71's nose shape will allow the surface wave effect to exist, but as the signal travels to the other (shadow) side, the edge will create an interruption -- scattering point -- that will radiate into free space away from the seeking radar.

IF wavelength is greater than diameter, that undulation from resonance will occur for the F-15 but not as pronounced for the SR-71 because of that interruption. This is why complex bodies create issues no less difficult to resolve in the resonance region if the complex body is DELIBERATELY shaped for RCS manipulations. This is why even APA, our man's source, had to admit that using 'long wavelengths' is not a solution against 'stealth'.

Russian / PLA Low Band Surveillance Radar Systems (Counter Low Observable Technology Radars)

Low band radars are not a panacea for the defeat of VLO (Very Low Observable) aircraft. Their angular accuracy has been until recently poor, and the required antenna size results in ungainly systems which are usually slow to deploy and stow, even if designed from the outset for mobility. The size and high power emissions of these radars, in types with limited mobility, makes them much easier to detect and destroy than typical mobile systems operating in the decimetric and centimetric bands, which can relocate rapidly after a missile shot.

This forum is the only place where his nonsense will be challenged. And with Chinese sources at that. This is why he acts as petulant as he does because this forum is one less place where his ego will be stroked.

 

[amalakas]

Here is a Chinese source and a clue to our Chinese friend who thinks that the resonance effect can be so simple to create and model...

An Error Occurred Setting Your User Cookie

There are no shortages of publicly available information on how as complex a body as an aircraft compared to a blimp or the simple sphere can screw up what was originally believed to be simple by overwhelming said complex body with wavelengths that matches or larger than target dimensions.

Another example...

ScienceDirect.com - AEU - International Journal of Electronics and Communications - Extraction of electromagnetic target poles from multiple scattered fields with damped Min-norm method

Complex bodies create multiple interruptions during the travel time and distance of the impinging wave and each scattering point is called a 'pole'.

Another example...


How to compensate for these disturbances is not to eliminate them from calculations but to increase the complexity of the algorithms and it all returned to the simple sphere and the 10-lambda rule,which our man omitted from his 'discussion' because he does not understand how all these things integrate.

That undulation is because of the signal continually wrapping itself around the sphere IF its wavelength is greater than sphere/cylinder diameter, aka the '10-lambda' rule. As the wavelength/diameter ratio increases that undulation disappear because the electrical path (diameter) is too great and signal loss via 'leaky waves' eliminate that 'wrapping' around effect.

Which lead us to this point...

The SR-71's nose shape will allow the surface wave effect to exist, but as the signal travels to the other (shadow) side, the edge will create an interruption -- scattering point -- that will radiate into free space away from the seeking radar.

IF wavelength is greater than diameter, that undulation from resonance will occur for the F-15 but not as pronounced for the SR-71 because of that interruption. This is why complex bodies create issues no less difficult to resolve in the resonance region if the complex body is DELIBERATELY shaped for RCS manipulations. This is why even APA, our man's source, had to admit that using 'long wavelengths' is not a solution against 'stealth'.

Russian / PLA Low Band Surveillance Radar Systems (Counter Low Observable Technology Radars)

This forum is the only place where his nonsense will be challenged. And with Chinese sources at that. This is why he acts as petulant as he does because this forum is one less place where his ego will be stroked.

I believed I started questioning my sanity when he proposed chinese to use statistical mean to extrapolate a "tracking" for an F-22.

I really don't know what to say.

 

[Speeder 2]

Here is a Chinese source and a clue to our Chinese friend who thinks that the resonance effect can be so simple to create and model...

An Error Occurred Setting Your User Cookie

There are no shortages of publicly available information on how as complex a body as an aircraft compared to a blimp or the simple sphere can screw up what was originally believed to be simple by overwhelming said complex body with wavelengths that matches or larger than target dimensions.

Another example...

ScienceDirect.com - AEU - International Journal of Electronics and Communications - Extraction of electromagnetic target poles from multiple scattered fields with damped Min-norm method

Complex bodies create multiple interruptions during the travel time and distance of the impinging wave and each scattering point is called a 'pole'.

Another example...


How to compensate for these disturbances is not to eliminate them from calculations but to increase the complexity of the algorithms and it all returned to the simple sphere and the 10-lambda rule,which our man omitted from his 'discussion' because he does not understand how all these things integrate.

That undulation is because of the signal continually wrapping itself around the sphere IF its wavelength is greater than sphere/cylinder diameter, aka the '10-lambda' rule. As the wavelength/diameter ratio increases that undulation disappear because the electrical path (diameter) is too great and signal loss via 'leaky waves' eliminate that 'wrapping' around effect.

Which lead us to this point...

The SR-71's nose shape will allow the surface wave effect to exist, but as the signal travels to the other (shadow) side, the edge will create an interruption -- scattering point -- that will radiate into free space away from the seeking radar.

IF wavelength is greater than diameter, that undulation from resonance will occur for the F-15 but not as pronounced for the SR-71 because of that interruption. This is why complex bodies create issues no less difficult to resolve in the resonance region if the complex body is DELIBERATELY shaped for RCS manipulations. This is why even APA, our man's source, had to admit that using 'long wavelengths' is not a solution against 'stealth'.

Russian / PLA Low Band Surveillance Radar Systems (Counter Low Observable Technology Radars)

This forum is the only place where his nonsense will be challenged. And with Chinese sources at that. This is why he acts as petulant as he does because this forum is one less place where his ego will be stroked.

Yo Gambit old bean, long time no see, how's your pumping going lately? Judging this posr of yours, dare I say that without my frenquent presence you and your usual mate (I mean you, amalaks, say hello!) have been pumping out of charts?



This forum is the only place where someone's nonsense will be challenged.

I fully agree!


In fact, the principle of what Martian argues is NOT wrong, but correct, even though the detailed method is perhaps over-simplified (e.g. moving avg part). And contrary to what you intended to pump, your quotations just proved he’s right instead . :


This principle deals with 2 things: 1 is to collect raw data and 2 is to model them.

Your first quotation (science.direct) is to try to prove that to collect resonance points is hard - well, of course it is and who said no? while your second quotation ( the French essay) is to provide one way trying to model it other than traditional Dmin-norm method, both of which are pretty primitive ones to me though to be honest.

Now, it comes to one of my territories: advanced modelling of complex phenomena. Hence fortunately I don't need to quote what others say as you do, because, for once, I am the darn source here when talking about modelling, oke? the expert one in fact

1. there is no fixed way ( only conventional one, the one, like what you google that you do with a passion, accepted by the mainstream which usually represents the dumbstream) of how to collect raw data a.k.a. resonance frequencies (target poles). There are many ways to define the how and what raw data one needs to collect, and what methodology and factors one intends for his modelling.

2. There is no fixed way, contrary to what you try to argue, on how to separate the noises from the core pole frequencies. Increasing the complexity of algorithms, as you argue, is only one way to tackle it, but not necessarily, or not definitely, the only way. There are many models to my expert knowledge that do a good job in eliminating, so called “taking out” noises without increase unnecessary complexity which leads to unwanted increase of computing power & time consumed.

3.The principle is provided that the Chinese have managed to collect enough resonance frequencies emitted by F-22 by effective/smartly re-arranging their radar frequencies etc I don't care, it is both theoretically and practically *entirely* feasible to have a reasonablely high quality result of where is F-22 by deploying state-of-art (means you can't google it) modelling methods which are not in the public domain.

Aforementioned modelling in principle are not that too different from advanced financial modelling deployed in areas such as ones for high-frequency trading and other proprietary models of quant hedge funds, albeit with slight adjustments. From some angles they are even *much* less complex than the latter, since

i) F-22 is mission-driven thus its fly pattern is non-random;

ii) its movements, if we artificially assume some key resonance frequency points for the sake of argument, are not stochastic but path-dependent and even linear (!) in many cases, and

iii) its paths are predetermined, in the sense that it won't go straight into heavily-monitored/defended radar zones of the East and North China but in between and along the border blind points... this could eliminate many flight paths and further limit the scope of the potential ones...all in all very helpful for modelling.

Therefore, Gambit old chap, yes, there’s no shortage of publicly available info on complex bodies and their modelling, but almost all of them are way off the mark as the good ones cost a lot of money thus not for free. So don't quote me some irrelevant info on this topic to fill the page and gain sympathies of the ignorant many. As I said, as along as China manages to get the full raw data (even with noises) one way or another I don’t care, to determine where more or less exactly is F-22 is "impossible" (errr...for the nuts), but do-able!

 

[amalakas]

Yo Gambit old bean, long time no see, how's your pumping going lately? Judging this posr of yours, dare I say that without my frenquent presence you and your usual mate (I mean you, amalaks, say hello!) have been pumping out of charts?



This forum is the only place where someone's nonsense will be challenged.

I fully agree!


In fact, the principle of what Martian argues is NOT wrong, but correct, even though the detailed method is perhaps over-simplified (e.g. moving avg part). And contrary to what you intended to pump, your quotations just proved he’s right instead . :


This principle deals with 2 things: 1 is to collect raw data and 2 is to model them.

Your first quotation (science.direct) is to try to prove that to collect resonance points is hard - well, of course it is and who said no? while your second quotation ( the French essay) is to provide one way trying to model it other than traditional Dmin-norm method, both of which are pretty primitive ones to me though to be honest.

Now, it comes to one of my territories: advanced modelling of complex phenomena. Hence fortunately I don't need to quote what others say as you do, because, for once, I am the darn source here when talking about modelling, oke? the expert one in fact

1. there is no fixed way ( only conventional one, the one, like what you google that you do with a passion, accepted by the mainstream which usually represents the dumbstream) of how to collect raw data a.k.a. resonance frequencies (target poles). There are many ways to define the how and what raw data one needs to collect, and what methodology and factors one intends for his modelling.

2. There is no fixed way, contrary to what you try to argue, on how to separate the noises from the core pole frequencies. Increasing the complexity of algorithms, as you argue, is only one way to tackle it, but not necessarily, or not definitely, the only way. There are many models to my expert knowledge that do a good job in eliminating, so called “taking out” noises without increase unnecessary complexity which leads to unwanted increase of computing power & time consumed.

3.The principle is provided that the Chinese have managed to collect enough resonance frequencies emitted by F-22 by effective/smartly re-arranging their radar frequencies etc I don't care, it is both theoretically and practically *entirely* feasible to have a reasonablely high quality result of where is F-22 by deploying state-of-art (means you can't google it) modelling methods which are not in the public domain.

Aforementioned modelling in principle are not that too different from advanced financial modelling deployed in areas such as ones for high-frequency trading and other proprietary models of quant hedge funds, albeit with slight adjustments. From some angles they are even *much* less complex than the latter, since

i) F-22 is mission-driven thus its fly pattern is non-random;

ii) its movements, if we artificially assume some key resonance frequency points for the sake of argument, are not stochastic but path-dependent and even linear (!) in many cases, and

iii) its paths are predetermined, in the sense that it won't go straight into heavily-monitored/defended radar zones of the East and North China but in between and along the border blind points... this could eliminate many flight paths and further limit the scope of the potential ones...all in all very helpful for modelling.

Therefore, Gambit old chap, yes, there’s no shortage of publicly available info on complex bodies and their modelling, but almost all of them are way off the mark as the good ones cost a lot of money thus not for free. So don't quote me some irrelevant info on this topic to fill the page and gain sympathies of the ignorant many. As I said, as along as China manages to get the full raw data (even with noises) one way or another I don’t care, to determine where more or less exactly is F-22 is "impossible" (errr...for the nuts), but do-able!

Tell me oh wise and knowledgeable one.

How will your model distinguish between the raw data of (and I am being lenient here) two F-22s feeding your system.

I'll save you the trouble, it can't !

 

[Speeder 2]

Tell me oh wise and knowledgeable one.

How will your model distinguish between the raw data of (and I am being lenient here) two F-22s feeding your system.

I'll save you the trouble, it can't !

Oh wise and knowldgeble one answers:

unless the "2" F-22 are sticking together, quite figuratively, creating flying paths 100% identical to each other from all angles all the time hence by definition "2" becoming 1, a decent model can, by bootstrapping just for a simple example, seperate the two as easy and as natural as a Greek chef (prehaps I overestimate the Greeks here nonetheless) seperates pork from chicken, or a bond trader seperates the seemingly "identical" streams of numbers along Coca Cola 10 yrs swap curve from Pepsi 10 yrs convertable curve.

 

[Martian2]

The real reason F-22 Raptor was canceled: Superseded by Chinese military technology

1. The Serbs shot down a state-of-the-art F-117 stealth fighter in 1999.

2. Chinese military technology, funding, low-band radars, supercomputing power, and network defenses are magnitudes beyond what the Serbs were capable. The integration of a variety of low-band radars, bi-static radars, multi-static radars, airborne AWACS, triangulation, tracking through "statistical averaging over time," and other advanced techniques should easily allow China to locate and track a F-22.

3. Since the public unveiling of the F-117 and B-2 in 1988, China has had 24 years to prepare in the shooting down of a stealth aircraft.

4. I hope you guys aren't dumb enough to believe the public explanation that the F-22 was canceled due to budget pressure. Behind closed doors, the Senate oversight committee receives classified reports of the true strength of Chinese air defenses.

This is simple common sense. Why would the United States cancel its most technologically advanced F-22 air-superiority fighter? The obvious answer is the U.S. wouldn't cancel it unless the F-22 was no longer effective for its intended purpose of fighting a near-peer (i.e. China).

I can't prove it (because I don't have access to classified reports), but the only logical explanation is the U.S. government has concluded the F-22 is no longer a trump card against China. Hence, the production of the F-22 was intentionally halted. The F-22 is unsuitable, because of its short combat radius of 471 miles and/or the Chinese air defense network.

In conclusion, shooting down a F-22 is well within China's technological capability. That is the expected outcome of a near-peer in military technology (e.g. a country that can build its own J-20 Mighty Dragon all-aspect stealth fighter). However, the Serbs will always own the distinction of being the first to shoot down a at-the-time state-of-the-art stealth fighter.

----------

Lockheed Martin F-22 Raptor - Wikipedia, the free encyclopedia

"President Obama signed the National Defense Authorization Act for Fiscal Year 2010 in October 2009, without F-22 funding.[84][85]"

 

[amalakas]

Oh wise and knowldgeble one answers:

unless the "2" F-22 are sticking together, quite figuratively, creating flying paths 100% identical to each other from all angles all the time hence by definition "2" becoming 1, a decent model can, by bootstrapping just for a simple example, seperate the two as easy and as natural as a Greek chef (prehaps I overestimate the Greeks here nonetheless) seperates pork from chicken, or a bond trader seperates the seemingly "identical" streams of numbers along Coca Cola 10 yrs swap curve from Pepsi 10 yrs convertable curve.

haha, it ain't the same and you know it.

stop selling it.

and you example is not suitable.. think about it.

(see ..and no insults in my answer)


you really can't see the flaw in your reasoning???

 

[gambit]

Oh wise and knowldgeble one answers:

unless the "2" F-22 are sticking together, quite figuratively, creating flying paths 100% identical to each other from all angles all the time hence by definition "2" becoming 1, a decent model can, by bootstrapping just for a simple example, seperate the two as easy and as natural as a Greek chef (prehaps I overestimate the Greeks here nonetheless) seperates pork from chicken, or a bond trader seperates the seemingly "identical" streams of numbers along Coca Cola 10 yrs swap curve from Pepsi 10 yrs convertable curve.

Your friend's source had to admit that the meters length freqs ALREADY have very poor angular resolution, plus there is this...

Definition: radar resolution cell

radar resolution cell: The volume of space that is occupied by a radar pulse and that is determined by the pulse duration and the horizontal and vertical beamwidths of the transmitting radar. Note: The radar cannot distinguish between two separate objects that lie within the same resolution cell.

Long wavelengths inevitably produces very wide beam, so in order to have beamwidth that matches the resolution capability of the decimetric and centimetric bands...

Over-the-horizon radar - Wikipedia, the free encyclopedia

In order to achieve a beamwidth of 1/2 degree at HF, an antenna array several kilometres long is required.

Oh, yeah......Several kms wide...Very 'portable' there...And very 'easily' hidden from sight as well.

Clue for you, conscript reject, we have been practicing the tactic of hiding multiple attackers inside a resolution cell long before you were borned. It drove the Soviets nuts even when we used the old F-111, of which I was on.

The real reason F-22 Raptor was canceled: Superseded by Chinese military technolog

Bunk.

1. The Serbs shot down a state-of-the-art F-117 stealth fighter in 1999.

The F-117 flew over 800 sorties. One out of 800 is not an air defense combat record to boast about.

The F-117 is/was hardly 'state of the art'. This is sheer hyperbole to suit your fanciful argument that somehow US 'stealth' aircraft is 'easily' defeated by Chinese methods.

The F-117:

- Used the FLCS from the F-16. How is that 'state of the art'?

- Have no radar. How is that 'state of the art'?

2. Chinese military technology, funding, low-band radars, supercomputing power, and network defenses are magnitudes beyond what the Serbs were capable. The integration of a variety of low-band radars, bi-static radars, multi-static radars, airborne AWACS, triangulation, tracking through "statistical averaging over time," and other advanced techniques should easily allow China to locate and track a F-22.

Has yet to be proven as WORKABLE.

3. Since the public unveiling of the F-117 and B-2 in 1988, China has had 24 years to prepare in the shooting down of a stealth fighter.

Without a low observable body to test? Doubtful.

4. I hope you guys aren't dumb enough to believe the public explanation that the F-22 was canceled due to budget pressure. Behind closed doors, the Senate oversight committee receives classified reports of the true strength of Chinese air defenses.

This is simple common sense. Why would the United States cancel its most technologically advanced F-22 air-superiority fighter? The obvious answer is the U.S. wouldn't cancel it unless the F-22 was no longer effective for its intended purpose of fighting a near-peer (i.e. China).

I can't prove it (because I don't have access to classified reports), but the only logical explanation is the U.S. government has concluded the F-22 is no longer a trump card against China. Hence, the production of the F-22 was intentionally halted. The F-22 is unsuitable, because of its short combat radius of 471 miles and/or the Chinese air defense network.

In conclusion, shooting down a F-22 is well within China's technological capability. That is the expected outcome of a near-peer in military technology (e.g. a country that can build its own J-20 Mighty Dragon all-aspect stealth fighter). However, the Serbs will always own the distinction of being the first to shoot down a at-the-time state-of-the-art stealth fighter.

----------

Lockheed Martin F-22 Raptor - Wikipedia, the free encyclopedia

"President Obama signed the National Defense Authorization Act for Fiscal Year 2010 in October 2009, without F-22 funding.[84][85]"

If you cannot prove it then you have nothing to go on. That is the real logic.

 

[Martian2]

By the way Gambit, I don't read your posts. You have become a troll like Amalakas.

It doesn't matter the logic or substance of my posts, you two trolls will always say "bunk" in a knee-jerk reaction. That is not a substantive argument.

You can go ahead and keep up your anti-China rhetoric. Just thought you should know, I don't read your garbage.

 

[amalakas]

By the way Gambit, I don't read your posts. You have become a troll like Amalakas.

It doesn't matter the logic or substance of my posts, you two trolls will always say "bunk" in a knee-jerk reaction. That is not a substantive argument.

You can go ahead and keep up your anti-China rhetoric. Just thought you should know, I don't read your garbage.

First of all mister, it is not anti-china rhetoric. And if anyone is a troll , it is you.

your theories are at best laughable, and I tried to give them some basis for argument at least, but you are just conjuring things out of thin air. No basis whatsoever. A mix of things put together than make a mess.


* you cannot triangulate because your space will have more than one planes in it. You can't make viable cells of triangulation. Moreover, if you have a decoy or a conventional plane in there too, your plan shoots to hell faster than ghostrider.

* You cannot use statistical average because you don't have a single source for data.

* you cannot use statistical average because even to get to that point you imply that you get tracking from an L-band radar. That is not the real case scenario. You will simply not get tracking of a LO body from an L-band radar.

* You cannot use statistical models for predicting the position of the ghost pings you get in a sporadic fashion because some of them will be false or not even belong to the same plane, not to mention few and far apart in both space and time.

 

[gambit]

By the way Gambit, I don't read your posts. You have become a troll like Amalakas.

It doesn't matter the logic or substance of my posts, you two trolls will always say "bunk" in a knee-jerk reaction. That is not a substantive argument.

You can go ahead and keep up your anti-China rhetoric. Just thought you should know, I don't read your garbage.

Do not care. This is not about you but about the readers who are not interested in stroking your ego. Keep your nonsense over at your playgrounds where there are plenty of gullible Chinese who will not hesitate to swallow everything you say.

 

[gambit]

Yo Gambit old bean, long time no see, how's your pumping going lately? Judging this posr of yours, dare I say that without my frenquent presence you and your usual mate (I mean you, amalaks, say hello!) have been pumping out of charts?

Your previous presence never mattered much since you never contributed anything of worth that is RELEVANT to the topic anyway. Go and pump yourself elsewhere.

This forum is the only place where someone's nonsense will be challenged.

I fully agree!

Good.

In fact, the principle of what Martian argues is NOT wrong, but correct, even though the detailed method is perhaps over-simplified (e.g. moving avg part).

Grossly over-simplified. But that is the extent of his knowledge. Keep in mind he is a confused Chinese-American who have no relevant experience let alone military experience.

And contrary to what you intended to pump, your quotations just proved he’s right instead . :

Anyone can be correct at the theoretical level. Unfortunately, Chinese engineers who have relevant experience proved your man, not necessarily wrong, but woefully inadequate. Or did you missed those Chinese names in one of my sources?

This principle deals with 2 things: 1 is to collect raw data and 2 is to model them.

Your first quotation (science.direct) is to try to prove that to collect resonance points is hard - well, of course it is and who said no? while your second quotation ( the French essay) is to provide one way trying to model it other than traditional Dmin-norm method, both of which are pretty primitive ones to me though to be honest.

Aaaawww...Are we supposed to be 'impressed'? Not...

ScienceDirect.com - AEU - International Journal of Electronics and Communications - Extraction of electromagnetic target poles from multiple scattered fields with damped Min-norm method

Mustafa Secmen

Electrical and Electronics Engineering Department, Yasar University, Bornova, 35100, Izmir, Turkey
Received 22 September 2011. Accepted 27 February 2012. Available online 28 March 2012.

In this study, the estimation of complex natural resonance frequencies (target poles) by using damped minimum-norm (DMin-norm) method is presented. The method mainly utilizes from the scattered fields belonging to multiple aspect angle/polarization cases of a target in resonance scattering region. By employing DMin-norm algorithm, the proposed method constitutes a function from which target poles can be efficiently extracted as its roots. However, the method in its conventional form should be executed as many times as the number of scattered fields to collect sufficient number of resonance frequencies. Therefore, the method is further improved in terms of computational time to acquire target poles with a single process for multiple scattered data. The described method is applied to a dielectric sphere having high number of target poles and good agreement between estimated and theoretical poles is observed.

Why not take some time and tell Senor Secmen how out of date he really is.

But if you have any relevant experience which is radar detection you would have known that data analysis in radar detection depends entirely upon the quantity and quality of data RECEIVED. The Doppler component is pretty much standard issued in multi-purpose radars but if it is not available due to NON-radial movement of the target, why bother to call it up?

Radial Velocity: measured by Doppler radars

Doppler radars can measure the component of the velocity of targets toward or away from the radar. This component is called the "radial velocity".

If the target is moving sideways so that its distance relative to the radar does not change, the radar will record zero radial velocity for that target.

You do know how the Doppler component works, right?

In shaping for RCS control, method of moment (MoM) is quite 'primitive' but it is still being used when applicable.

Another example is in flight control laws. Pure pursuit laws are the simplest and by your egotistical standard: primitive. And yet PP is an absolute requirement and PP serves as the foundation for composite FLCS laws in every digital FLCS from missiles to fighter aircrafts. You mean you did not know about such a thing as 'flight control laws'? Sorry if it is too 'primitive' for you.

Now, it comes to one of my territories: advanced modelling of complex phenomena. Hence fortunately I don't need to quote what others say as you do, because, for once, I am the darn source here when talking about modelling, oke? the expert one in fact

I doubt that. If you are then it make you an intellectually dishonest expert since your friend have made one technical blunder after another usually from ignorance and ego. Chinese solidarity comes first at the expense of honesty, right?

1. there is no fixed way ( only conventional one, the one, like what you google that you do with a passion, accepted by the mainstream which usually represents the dumbstream) of how to collect raw data a.k.a. resonance frequencies (target poles). There are many ways to define the how and what raw data one needs to collect, and what methodology and factors one intends for his modelling.

True...But in radar detection, you are at the mercy of the target, so either you cast as wide a net in terms of methodology as possible, from Doppler to space-time adaptive to SAR to iSAR and many more, to cover for every possible contingency, or you restrict your system to single use, such as the moving target indicator (MTI) radar.

2. There is no fixed way, contrary to what you try to argue, on how to separate the noises from the core pole frequencies.

Increasing the complexity of algorithms, as you argue, is only one way to tackle it, but not necessarily, or not definitely, the only way. There are many models to my expert knowledge that do a good job in eliminating, so called “taking out” noises without increase unnecessary complexity which leads to unwanted increase of computing power & time consumed.

Nowhere did I even implied so. But for the interested readers, noise comes from primarily two sources: background and self generated. Internally generated noise, which is as inevitable as background, is treated as zero mean Gaussian and can be simplistically eliminated. The higher the quality of the hardware, the easier it is to eliminate hardware related noise.

What Senors S. G. Wang, X. P. Guan, X. Y. Ma, D. W. Wang, and Y. Su of the National University of Defense Technology of Changsha, China, referred to was background radiation that contaminated the many scattering points (poles) of a complex body. Regardless of wavelengths employed, there will be signal loss because of the inverse square law TO the target, target caused losses such as absorbers, and the same inverse square law FROM the target back to the seeking radar.

Cosmic background radiation (CBR) can also be treated as zero mean Gaussian and easily eliminated. But signals or rather 'clutter' from flora, topography, and/or water have different distributions such as lognormal or Weibull, cannot be so easily discarded, worst of all is sea state or the Douglas Sea Scale => Douglas Sea Scale - Wikipedia, the free encyclopedia

Waves at sea generally fall under two main categories: capillary and gravity.

Capillary wavelengths are usually 2 cm or less. Surface tension is the retaining or 'restoring' force.

On the other hand, gravity wavelengths can range from a few hundreds meters to about one meter, give or take a few cm. Gravity waves also fall under two sub-categories: sea and swell. The sea state is when the waves are created/blown by the wind. The swell state is when the waves are no longer under the influence of the wind that created them.

These are not independent and identically distributed (IID) noise. The surface they travel upon is sufficiently stable that it can act as a low pass filter for us to reduce some algorithm complexity and processing time.

Beamwidth also affect the amount of these signals received and that will increase or decrease processing time. Grazing angle and multi-paths propagation will affect the quantity and quality of data received and in that data includes noise. There is constant false alarm (CFAR) processing and there is cell averaging constant false alarm (CACFAR). This is not yet considering ECM, which is very much noise.

And you are telling everyone that increasing algorithm complexity is not necessary when modern air combat require the mission to be able to change from high altitude to Earth grazing within a few seconds?

3.The principle is provided that the Chinese have managed to collect enough resonance frequencies emitted by F-22 by effective/smartly re-arranging their radar frequencies etc I don't care, it is both theoretically and practically *entirely* feasible to have a reasonablely high quality result of where is F-22 by deploying state-of-art (means you can't google it) modelling methods which are not in the public domain.

This is wishful thinking at best. Yeah...We will grant you that it is theoretically possible. So is building the Death Star.

Aforementioned modelling in principle are not that too different from advanced financial modelling deployed in areas such as ones for high-frequency trading and other proprietary models of quant hedge funds, albeit with slight adjustments. From some angles they are even *much* less complex than the latter, since

i) F-22 is mission-driven thus its fly pattern is non-random;

ii) its movements, if we artificially assume some key resonance frequency points for the sake of argument, are not stochastic but path-dependent and even linear (!) in many cases, and

iii) its paths are predetermined, in the sense that it won't go straight into heavily-monitored/defended radar zones of the East and North China but in between and along the border blind points... this could eliminate many flight paths and further limit the scope of the potential ones...all in all very helpful for modelling.

Right...So what you are doing is imposing your own limitations upon the USAF on how to deploy and operate the F-22 for the sake of giving some technical credibility to your friend's extremely dubious arguments.

Therefore, Gambit old chap, yes, there’s no shortage of publicly available info on complex bodies and their modelling, but almost all of them are way off the mark as the good ones cost a lot of money thus not for free. So don't quote me some irrelevant info on this topic to fill the page and gain sympathies of the ignorant many. As I said, as along as China manages to get the full raw data (even with noises) one way or another I don’t care, to determine where more or less exactly is F-22 is "impossible" (errr...for the nuts), but do-able!

The difference between me and you Chinese boys is that I do not insult the intelligence of the readers, or as you put it the 'dumbstream', even though I realize they are lay people ignorant of the basics of this complex subject, I give them credible sources and keyword searches for them to verify for themselves. What I provide is not about proving me right or wrong but about giving them the necessary direction for them to verify for themselves. I do not care how deep anyone dig. For me, I travels regularly between Edwards, Hill, and Nellis. You can search for yourself and see what goes on at those bases. I know better than what your friend claim and try to convince people that he is right. Whereas I do not try to convince people that I am right, only that they look in this or that direction.

So yes, there are plenty of publicly available sources on how your friend's claims should be looked at with a critical eye. Not with blind approval and praise like over at your playgrounds. Go there if all you want is a mutual admiration society in a circle jerk inside the echo chamber they initially feared it will become -- and did.