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Radar Ranges Of Different Fighters

How are the modules related to the level of Fourier transform?
that's parallel processing exemplified at best.. not the complexity of the transform.
Its like assuming that ten 166Mhz processors packaged together will become 2 gig processors.

I was asking about the relation of Fourier and Laplace transforms in packing of modules... I was very bad at Fourier series though..


But that's how we call it... Chinese architecture looked similar to the Russian so I asked.

Don't know how many of you have seen a knocked down ESA I have seen Bars all knocked up... but that was from about 20 meters No camera allowed.
 
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Yes dear,

You jumped on my tail, and instead of producing some HARD evidence, you further sunk into the petty tit-for-tat bullsheet. Bring me evidence. I just showed you evidence from my side. Show some cojones and post some evidence for once. Otherwise either keep quite, or poke your own tail.

As for my evidence ... here's more

AN/APG 73 ... 2 channel AESA (LeftColumn 3rd Paragraph) The Naval Institute guide to world naval weapons systems, By Norman Friedman
AN/APG 79 ... 4 channel AESA (Fifth Paragraph) AN/APG-73 Radar System
Zhuk AE AESA (2nd Paragraph) Phazotron Zhuk AE AESA Radar

Show me evidence, from anywhere, that Irbis or Zhuk uses 8 Channel, or any other operational AESA for that matter. All operationall AESA have max 4 channels for now. If there is an operational AESA with 8-channel, thats news to me, and please do send me a link to study.

Also, you have absolutely no understanding of the level of Mathematics at work here, read up on Laplace and Fourier transforms and get back to me when you get an understanding whether 8th order fourier series is even required over here.

Regards,
Sapper

Studied Laplace Transform.

Starting Fourier transform. Any lecture here would be greatly appreciated and how it applies to signals for RADAR systems.


thanks.
 
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Studied Laplace Transform.

Starting Fourier transform. Any lecture here would be greatly appreciated and how it applies to signals for RADAR systems.


thanks.

What do you study ?

If Its related to electronics... there's a paper called Signals and Systems... and then you have Instruments too... where you can study about Radars.... If you have Interest buy extra books of some Russian writers in Tata-Macgraw Hill publications... they sell very good books on Radars and Signals cheap, simple and knowledgeable... any one can understand but a Little Knowledge about Analog Electronics helps.
 
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What do you want me to prove here your source itself claimed 3-4 modules per sub-array... an array can consist of 2-3 such sub arrays while packing them in racks in the antenna disk.

Sorry I am very weak at mathematics and your Bachelor level Fourier series went over my head care to explain how does it determine the the packing arrangement of an antenna... don't worry I am not that weak.... lol.......

can you count the number of modules in there ?

NIIP-AESA-X-Band-Brochure-2S.jpg

Dear,

Number of Modules is Totally different thing, Transmit/Receive Channels is totally different.

In normal PD Radar, there is only one big-a$s transmitter that transmits a specific frequency pulse in a 60-deg cone-shaped area, and any craft in that area is radar-illuminated and the reflections of that frequency coupled with its doppler shift are used to track that target. Now the problem with this is that the radar beam becomes diluted the farther it goes, calculated using Inverse-Square law. Image a huge powerful bulb, a One-Meter-Square Object one meter away will be extremely well lit, but the same object placed a kilometer away will only get a millionth of the light from the same source.

In AESA, there are as many transmitter as the number of T/R-Modules, and every module tries to produce a penicl radar beam. Now if 1000 modules of the radar are targetting its pencil beam on a very small target area e.g. One-Degree-Cone, compared to the 60 degree cone of PD, the beam strength will be immensly high, and the range and resistance to clutter will be greatly increased. This is almost as if the target is being illuminated by 1000 lasers, instead of the single big-fat lightbulb. This produces much more intense radar pulse than PD, for the same amount of gross tranmission power.

Now the thing is that to produce this PENCIL beam (a very narrow radar beam, like laser), multiples of the same frequency are used to Square up the Sinosoidal transmission frequency/channel. Thats where Fourier series comes in, and thats what is meant by single, dual, tripple and quad channel transmission module. The target of AESA T/R modules is to produce a single Square-Pencil-Pulse-Beam, to eliminate the unwanted radar reflections from things that are not in the targetted scanning zone. If the produced beam is a perfect square, and you get a very weak reflection, it means that there is a target inside the targetted zone, and the computer shows it on the screen. If the produces beam has powerful sidelobes, then the reflected signal can be from a target inside the intended target zone, or it might be somewhere in the sidelobe area as well, thus the computer only decides only to show radar blip if the reflection is strong enough to be surely coming from the targetted zone and not from sidelobe zones, thus increasing clutter and well as reducing accuracy and range.

I am linking some picture from two differenct websites to explain briefly how a sinosoid can be modified into pencil/square beam by using 2nd, 3rd, 4rth & 5th fourier frequency harmonic channel.

Fourier Harmonics to get Square Wave (not pulse)
square-wave-sine3.jpg


Fourer Harminic Transmission to get Pencil-Beam/Square-Pulse (not wave)
approximation.gif



I hardly believe anyone will try to make operational modules based on 8th Harmonic T/R modules for AESA in near future. 4th and 5th order is itself too much to handle for now.

Regards,
Sapper
 
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Dear,

Number of Modules is Totally different thing, Transmit/Receive Channels is totally different.

In normal PD Radar, there is only one big-a$s transmitter that transmits a specific frequency pulse in a 60-deg cone-shaped area, and any craft in that area is radar-illuminated and the reflections of that frequency coupled with its doppler shift are used to track that target. Now the problem with this is that the radar beam becomes diluted the farther it goes, calculated using Inverse-Square law. Image a huge powerful bulb, a One-Meter-Square Object one meter away will be extremely well lit, but the same object placed a kilometer away will only get a millionth of the light from the same source.

In AESA, there are as many transmitter as the number of T/R-Modules, and every module tries to produce a penicl radar beam. Now if 1000 modules of the radar are targetting its pencil beam on a very small target area e.g. One-Degree-Cone, compared to the 60 degree cone of PD, the beam strength will be immensly high, and the range and resistance to clutter will be greatly increased. This is almost as if the target is being illuminated by 1000 lasers, instead of the single big-fat lightbulb. This produces much more intense radar pulse than PD, for the same amount of gross tranmission power.

Now the thing is that to produce this PENCIL beam (a very narrow radar beam, like laser), multiples of the same frequency are used to Square up the Sinosoidal transmission frequency/channel. Thats where Fourier series comes in, and thats what is meant by single, dual, tripple and quad channel transmission module. The target of AESA T/R modules is to produce a single Square-Pencil-Pulse-Beam, to eliminate the unwanted radar reflections from things that are not in the targetted scanning zone. If the produced beam is a perfect square, and you get a very weak reflection, it means that there is a target inside the targetted zone, and the computer shows it on the screen. If the produces beam has powerful sidelobes, then the reflected signal can be from a target inside the intended target zone, or it might be somewhere in the sidelobe area as well, thus the computer only decides only to show radar blip if the reflection is strong enough to be surely coming from the targetted zone and not from sidelobe zones, thus increasing clutter and well as reducing accuracy and range.

I am linking some picture from two differenct websites to explain briefly how a sinosoid can be modified into pencil/square beam by using 2nd, 3rd, 4rth & 5th fourier frequency harmonic channel.

Fourier Harmonics to get Square Wave (not pulse)
square-wave-sine3.jpg


Fourer Harminic Transmission to get Pencil-Beam/Square-Pulse (not wave)
approximation.gif



I hardly believe anyone will try to make operational modules based on 8th Harmonic T/R modules for AESA in near future. 4th and 5th order is itself too much to handle for now.

Regards,
Sapper

I showed you the Image... the Phase-shifors used in Bars are semiconductor... whether or not is it GaAs I am not sure since It was too far to be seen.... that image shows the sub-array arrangement of NIIP AESA in a single array.... which is already made... In AESA every module is like a different channel... Bars receive the feed from each chaneel which is the sent to duplexer and then to Receiver for signal processing... may be that's why they call like a Hybrid PESA/AESA.

Also since you raised the point about pencil beam.... it also matters on the size of whole antenna... the larger the antenna the sharper the beam hence better tracking as explains the 2nd graph.
 
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What do you study ?

If Its related to electronics... there's a paper called Signals and Systems... and then you have Instruments too... where you can study about Radars.... If you have Interest buy extra books of some Russian writers in Tata-Macgraw Hill publications... they sell very good books on Radars and Signals cheap, simple and knowledgeable... any one can understand but a Little Knowledge about Analog Electronics helps.

I study Electrical and Electronics.

I have studied Signals and Comm and all the Fourier, Laplace and Z transforms and the Dirac Delta functions. I even have the biographies of Joseph Fourier and Paul Dirac. What i meant was how Fourier is used for generating radar pulses, and as Sapper explained, for AESA systems.

I know mostly about FSK systems and the Frequency Doman and Time Domain.
 
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I study Electrical and Electronics.

I have studied Signals and Comm and all the Fourier, Laplace and Z transforms and the Dirac Delta functions. I even have the biographies of Joseph Fourier and Paul Dirac. What i meant was how Fourier is used for generating radar pulses, and as Sapper explained, for AESA systems.

I know mostly about FSK systems and the Frequency Doman and Time Domain.

I don't know how Fourier transforms or series are used for pulse generation. The phase-shifting is much simpler than Fourier. You just look at what angle you need the beam to be steered to and then shift the phase by the right amount so they all match up at that angle. Of course, you can also do some amplitude control to achieve beam shaping, which might involve some sort of Fourier transform over the angle space.

Where the Fourier transform is really used is for doppler based radars in the receiving circuit. This allows you to find the frequency shifted signal from the background noise.
 
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I showed you the Image... the Phase-shifors used in Bars are semiconductor... whether or not is it GaAs I am not sure since It was too far to be seen.... that image shows the sub-array arrangement of NIIP AESA in a single array.... which is already made... In AESA every module is like a different channel... Bars receive the feed from each chaneel which is the sent to duplexer and then to Receiver for signal processing... may be that's why they call like a Hybrid PESA/AESA.

Also since you raised the point about pencil beam.... it also matters on the size of whole antenna... the larger the antenna the sharper the beam hence better tracking as explains the 2nd graph.

Dear,

You are talking about this Module,

NIIP-AESA-X-Band-Brochure-2S.jpg


In this image there are two parts, Left and Right. These are probably two modules in a single casing as evident from two separate Bumps which are the antennae. OR, they may simply be the Transmit & Receive part of same module, then again we don't know whats on the other side. My guess is that both are separate modules, packaged as single slot in device and Receiver is on the other side. Notice that this is dual side circuit, and all the connection and power I/Os are on the other side of chip, while on US designs, its on left side.

Talking about the Right one only, there are eight signal amplifiers (the ones with heat sink on them, i.e. GaAs 5~15 Watt op-amp), so it seems it has 8 channels ... Wrong. There are 4 channels and 4 negative channels, because for QAM (Quadrature Amplitude Modulation, which all radars as well as AESA uses) to work, there must be two complementing signals I / Q, which have a 90 deg phase shift (further proof you'll find in a Radar-Basics, and a few US patent links further down the post).

Now open the Quadrature Amplitude Modulation page on wiki, and you'll find something very similar to these AESA modules. Notice that both have an I and Q component (also called positive and negative component in frequency domain). Also note that both are merged together to form the final signal. I am linking two diagrams from wiki for easier reference.

Transmitter
800px-QAM_transmitter.svg.png

Reciever
799px-QAM_receiver.svg.png


Now compare that picture with these US AESA production modules.
ARPA-MMIC-Brief-1992-1S.jpg

Caption :Two early US designed quad (4 channel) transmit receive modules, which are similar in design to the Phazotron modules used in the Zhuk AE (Image "MIMIC Phase I Briefing", March 25, 1992, approved for public release, Director ARPA DMO, April 6, 1995).

These designs are clearly 4 channel (not 8) as claimed by US themselves. But if you look closely on the bottom 1989 design (less visible in 1988 design due to lighting), every one of the four channel has two separate chips (the line of black chips, 2nd from right, with silver heat-sink/connector on right) , adjacent to one another. The inputs and outputs of both are joined after a special loopy circuit-wires with a black dot beside their joining point. This black dot is a micro capacitor, which ensures a 90 deg phase shift in RLC circuits. Then the outputs from four channels is joined to form a single output. Compare this to Russian design, and you'll see the same architecture, i.e. 8 op-amps, joined together for a single 4 channel output.

Now for the proof that radars in general as well as AESA use QAM. Open these Links, and search for the word "Quadrature".

Radar Basics
Low profile active electronically scanned antenna (AESA) for Ka-band radar systems
Patent-AESA-Ka-Band Summary (USA-2006)
Patent-AESA-Ka-Band Full-PDF (USA-2006)

Also, if you follow up on the text from where you posted the NIIP module picture, it catagorically states that this is quad-channel AESA design.

In short, the NIIP-module-picture shows a very high output (Big-A$s op-amps) quad-channel AESA design.

Regards,
Sapper
 
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Dear,

You are talking about this Module,

NIIP-AESA-X-Band-Brochure-2S.jpg


In this image there are two parts, Left and Right. These are probably two modules in a single casing as evident from two separate Bumps which are the antennae. OR, they may simply be the Transmit & Receive part of same module, then again we don't know whats on the other side. My guess is that both are separate modules, packaged as single slot in device and Receiver is on the other side. Notice that this is dual side circuit, and all the connection and power I/Os are on the other side of chip, while on US designs, its on left side.

Talking about the Right one only, there are eight signal amplifiers (the ones with heat sink on them, i.e. GaAs 5~15 Watt op-amp), so it seems it has 8 channels ... Wrong. There are 4 channels and 4 negative channels, because for QAM (Quadrature Amplitude Modulation, which all radars as well as AESA uses) to work, there must be two complementing signals I / Q, which have a 90 deg phase shift (further proof you'll find in a Radar-Basics, and a few US patent links further down the post).

Now open the Quadrature Amplitude Modulation page on wiki, and you'll find something very similar to these AESA modules. Notice that both have an I and Q component (also called positive and negative component in frequency domain). Also note that both are merged together to form the final signal. I am linking two diagrams from wiki for easier reference.

Transmitter
800px-QAM_transmitter.svg.png

Reciever
799px-QAM_receiver.svg.png


Now compare that picture with these US AESA production modules.
ARPA-MMIC-Brief-1992-1S.jpg

Caption :Two early US designed quad (4 channel) transmit receive modules, which are similar in design to the Phazotron modules used in the Zhuk AE (Image "MIMIC Phase I Briefing", March 25, 1992, approved for public release, Director ARPA DMO, April 6, 1995).

These designs are clearly 4 channel (not 8) as claimed by US themselves. But if you look closely on the bottom 1989 design (less visible in 1988 design due to lighting), every one of the four channel has two separate chips (the line of black chips, 2nd from right, with silver heat-sink/connector on right) , adjacent to one another. The inputs and outputs of both are joined after a special loopy circuit-wires with a black dot beside their joining point. This black dot is a micro capacitor, which ensures a 90 deg phase shift in RLC circuits. Then the outputs from four channels is joined to form a single output. Compare this to Russian design, and you'll see the same architecture, i.e. 8 op-amps, joined together for a single 4 channel output.

Now for the proof that radars in general as well as AESA use QAM. Open these Links, and search for the word "Quadrature".

Radar Basics
Low profile active electronically scanned antenna (AESA) for Ka-band radar systems
Patent-AESA-Ka-Band Summary (USA-2006)
Patent-AESA-Ka-Band Full-PDF (USA-2006)

Also, if you follow up on the text from where you posted the NIIP module picture, it catagorically states that this is quad-channel AESA design.

In short, the NIIP-module-picture shows a very high output (Big-A$s op-amps) quad-channel AESA design.

Regards,
Sapper

Those are 8 T/R module packed up in a single slot those double slot represent one full array of T/R channels... Zhuk-A is not a true AESA much like APG-79.... APG-77 and 81 are what which can be called as true AESA radars...not so sure about APG-81 though.

The problem which can be there due such packing is High power consumption even for illumination process... usually the practice off keeping a single slot for each modulation... which is usually done by different sub-arrays.... If the same is followed then this might be having a 8 channel modulator... and about the photo you showed about US sub-array used in APG-63... there is a similar photo with 4-channel modulator for the X-band AESA made for Tejas... I'll upload the photo when I find it in my drives... but it is not being adopted since they are insisting on a 8 channel one with smaller size.

Here the quad-channel sub-array design for Tejas X-Band AESA MMFCR.

compact3.jpg


That pen is Reynolds ball pen which many of you might be using.
 
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Those are 8 T/R module packed up in a single slot those double slot represent one full array of T/R channels... Zhuk-A is not a true AESA much like APG-79.... APG-77 and 81 are what which can be called as true AESA radars...not so sure about APG-81 though.

The problem which can be there due such packing is High power consumption even for illumination process... usually the practice off keeping a single slot for each modulation... which is usually done by different sub-arrays.... If the same is followed then this might be having a 8 channel modulator... and about the photo you showed about US sub-array used in APG-63... there is a similar photo with 4-channel modulator for the X-band AESA made for Tejas... I'll upload the photo when I find it in my drives... but it is not being adopted since they are insisting on a 8 channel one with smaller size.

Please post a picture along with manufacturer's claim of 8 channel AESA. If you ask me anything beyond 4rth or 5th channel is an utter waste of Precious space and most importantly much more precious Gross-Radar output.

If you use 1 x 64mm-sq chip for single channel, you might get 64 watt (just an example), now if you use same space and power input, and use two channels, you will have 2 x 32mm-sq chips, producing a 32 watt signal coupled with good accuracy. Using 3 channels, you'll have 3 x 22mm-sq chips, producing a 22 watt signal with superior accuracy, and with four channels, you'll get 4 x 16mm-sq chip, producting extremely accurate results, but with only 16 watt output power. If you go for 8 channel design, the figure comes out to be 8 x 8mm-sq chip, producing only 8 watt gross output but with only marginable increase in accuracy.

The Power output decrease as a linear function, i.e. for 1Cx64W, for 2Cx32W, 3Cx22W, 4Cx16W .. 8Cx8W (C=channel , W=Watt) .

On the other hand Accuracy only increases as an exponentially decreasing function, the calculations of which are very complex. I am posting an image of RMS-ERROR graph. Note: we only use Odd-Numbered Harmonics in fouriers, because thats where the drop in RMS-error occurs, i.e. when i say 4 channel, it means 1st Harmonic (fundamental freq), 3rd Harmonic, 5th Harmonic and 7th Harmonic.

fourier2.png


Now what this image shows is that, the accuracy has very little impact after 7th haarmonic. After that its only fractions of a percent improvement per channel.

Thus channels beyond 4 or 5, i.e. 7th or 9th harmonic are simply waste of money and power. Hope you understand.

Regards,
Sapper
 
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* Radar Name
* Radar Range
* Aircraft Range (Fuel)
* BVR missiles
* BVR missiles range for each missile 56KM, 80KM, etc..
* Future upgrades with sources.
* Current number of the type of the aircraft.
* Electronic counter measures system for each aircraft.

I can give you radar detection ranges & number in active duty.

Su-30MKI ~ 150
Radar Range - Confidential because the transmitter power is confidential. However some open source material indicates it's range between
140km-170km for 5m2 Target

MiG-29B ~ 51
Radar Range - 79.5km for 5m2 Target

MiG-29S ~ 10
RR - 91km for 5m2 Target

MiG-29UPG ~ 61 (upgrade currently underway)
RR - 120km for 5m2 Target

Mirage-2000UPG ~ 49 (upgrade currently underway)
RR - 105km for 5m2 Target

MiG-21 Bison ~ 110 (some are equipped with Kopyo-21i & some with Kopyo-M)
Kopyo-M - 80km for 5m2 Target
Kopyo-21i - 57km for 5m2 Target

Jaguar
Has no Radar

MiG-27
Has no Radar

Super Su-30MKI (upgrade in a year or 2)
No details available

Rafale (set to start arriving in 3 years)
No accurate details on its AESA radar.

----

F-16 Block52 ~ 18
RR - 105km for 5m2 Target

JF-17
RR - 85km for 5m2 Target(75km for 3m2 Target)

F-16 MLU
RR - 74km for 6m2 Target
 
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for thunder its 105 km for 5m2..

note :recent figures are not available the figures are way back before serial production. Some sources claim that some additional improvements have been made in range
 
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Dude, do you seriously think -
KLJ-7 which is a smaller radar(due to smaller nose cone of JF-17) than F-16's Block 52, has the same range as it?

If that range is for the J-10's KLJ-10 radar then it would be more believable. The Radar on Block 52 the APG-68(V)9, is the latest and the greatest mechanically scanned array on a F-16. So is CETC a more advanced defence complex than Northrop Grumman to have achieved this incredible feat?
 
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original post -ANTIBODY


one thing that i speculated [maybe wrongly] is the due to the sheer size of the mki , its kill probabilty distance/ no escape zone would be more and would favour sd10 coupled with jft -- so even even the 2 fighters detect each other at the same time.... even if the 2 missiles have same range ... sd10 might be fired earlier by the pilot with relatively better confidence of the firing pilot[not necessarily from the longest possible distance]

in this case please dont take into consideration the jammers etc ... as i want to know who will be able to fire first with better possible results

kind regards



via nabil --the first jft prototype had a frontal rcs of 2.6 m2
Current jft has much less
RCS OF Different Fighters

via chogy --Just eyeballing the airframe... as others have said, I would place it in the F-16 class,
RCS OF Different Fighters

The[dsi] intake reduces one of the three major forward scatters of an aircraft that typically represents between 30%-35% of the RCS of an aircraft.
http://www.grandestrategy.com/2007/1...for-third.html



my questions are -- can the rcs estimate be made roughly by just looking at the fighter? if yes where would you place the rcs of jft? whats is the direct/indirect effects of dsi on rcs reduction , if any


ive asked you questions for 2 different threads now .. in the earlier PM for the ''radar ranges of different fighters'' thread .. amd now for the ''rcs of different fighters'' thread

I am anxoiusly waiting for your replies
kind regards


gambit said:
You took several important variables out of the picture. Nothing wrong with that because from my experience, we do/did that all the time by either altering the physical structures of the targets or by 'handicapping' the radar via software if we cannot alter the physical structures.

If you sort of 'equalize' the fighters in every way, as highlighted below, then the burden of the kill falls ENTIRELY upon the weapon. We have done this in the past when we are faced with physically dissimilar 'adversaries' but we must 'equalize' them somehow. The most commonly used technique is to install radar enhancer on the smaller body to where the estimated RCS is within 5% of its adversary's RCS. To 'hack' a radar's software involved too much time, possible security breaches and worst of all -- copyright related crap.

Anyway...If two fighters detect each other at the same time, and even if one shoot later than his opponent, assuming both fighters know full well the range capability of his missile, then it depends on missile's sophistication such as g-rating, the type of flight controls system, fuel formulation and shapes because they affect thrust and burn duration, missile guidance avionics...

Aerospaceweb.org | Ask Us - Missile Control Systems
NASA Quest > Space Team Online

...In short, everything that we discuss about manned fighters, you can transfer to the missiles because a missile IS an aircraft that have a higher performance envelope because it does not have to worry about keeping a human alive.

Here is the problem for your scenario...If one fighter is physically larger than the other, does that mean it has a larger RCS as well? Not necessarily. Even a B-52 can have an RCS of a bird, but at a very far distance. The problem is that if both fighters detect each other at the same time despite being physically dissimilar, it mean both have the same RCS -- FROM THEIR RADARS' PERSPECTIVES. An RCS value depends on the transmitting radar's signal and data processing sophistication. It mean a physically smaller body can have the same RCS as the larger body at the same distance because radar sophistication varies widely between manufacturers.

If two fighters of physically dissimilar sizes detect each other at the same time, then it mean the larger fighter have the superior radar system to compensate for its larger physical dimensions. If we assume that both fighters have the same radar sophistication -- no matter what -- then your scenario is impossible. The larger fighter will be detected first and will die first REGARDLESS OF MISSILE SOPHISTICATION.

Let us use 1m2 at 100km distance for example. If both fighters that are physically dissimilar detect each other at the same time, it mean both fighters have the same RCS of 1m2 according to their respective radars' sophistication at 100 km distance. Get it?

It mean the smaller fighter have an inferior radar because if it have the same level of sophistication, it should have detected the physically larger fighter at 120 or even 150 km distance without itself being detected. In other words, assuming if both fighters have the same radar sophistication, the larger fighter would be 1m2 at 150 km distance while the smaller fighter would be 1m2 at 100 km distance. Who would die first? The larger fighter.

For your scenario that have an engagement between physically dissimilar fighters where both detect each other AT THE SAME TIME the smaller fighter must have an inferior radar, and if both shoot at roughly the same time, then it depends entirely upon missile sophistication for the kill.

The reason why I often say '150-200' km distance for 1m2 RCS is precisely because of variations in radar sophistication. That 50 km distance variable is a terrible figure but it is the truth about the industry. That figure is about the distance for several missiles so you can see how important it is to gain even just 5 km of further out detection distance.


Is it possible to have even a rough RCS value guesstimate for any fighter? No.

But...You can place it in the same class -- base upon 'eyeballing' -- as long as you have a reasonably accurate RCS value from one or several aircrafts that set the standard for that class. The clean F-16 pretty much set the bar for 'stealth', meaning you must get below 1m2 at 150-200 km distance in order to be a credible 'stealthy' threat. So can you say 2.85m2 at 121.8 km distance based upon pure eyeballing? No.

Personally, I would place the JF into the F-16 class based upon what I personally know about the F-16's RCS and based upon my 'eyeballing' the JF.

I do not know how your friend had this 2.6 figure 'confirmed' to him. Absent assurance on how this figure came to be, such as if it was measured in isolation as in enclosed anechoic EM chamber, that decimal level of precision is dubious.

Same for the RCS reduction value of the DSI structure. Each DSI structure must be carefully custom tailored for the aircraft out of aerodynamic demands and because of that, its purported RCS reduction or RCS contributorship compare to the diverter plate is difficult to assess in regard to that percentage you cited. I mean...Were there measurements on the design that have the diverter plate assembly? If the design never intended to have the diverter plate in the first place, then how credible is that 30-35% figure?

That does not mean the DSI structure is not beneficial in trying to effect RCS contributorships from diverse structures on as complex a body like an aircraft. It is beneficial because you want to have as low a contributorship FOR EACH structure as possible. On the other hand, if there is one or if there are several large contributorships from several different structures that utterly dominate measurements then it is pointless to debate on whether to install the diverter plate or the DSI structure.

To sum it up...It is reasonable to presume a 'class' but not reasonable to declare a value, and if said declaration involve a decimal point, time to be suspicious.


just thought to share some info -- credits to gambit
 
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