Chinese Radar Developments - KLJ series and others

ougoah

Brigadier
Registered Member
Can we come back to the Chinese Flankers please?

@Tam @siegecrossbow and any other participant in that radar conversation. Could you also please continue the interesting discussion on J-10B radar in the radar thread?

I also assumed (due to popular opinion and nothing else) that the J-10B used a PESA radar but it seems that the only real indicator that it might be a PESA are the IFF modules which honestly probably don't prove anything. Does an AESA radar absolutely not have IFF modules designed this way due to whatever engineering compromises?

Anyway, please continue that discussion! ... on the radar thread.
 

Tam

Brigadier
Registered Member
@Tam @siegecrossbow and any other participant in that radar conversation. Could you also please continue the interesting discussion on J-10B radar in the radar thread?

I also assumed (due to popular opinion and nothing else) that the J-10B used a PESA radar but it seems that the only real indicator that it might be a PESA are the IFF modules which honestly probably don't prove anything. Does an AESA radar absolutely not have IFF modules designed this way due to whatever engineering compromises?

Anyway, please continue that discussion! ... on the radar thread.

Lots of PESA don't have IFF spread across their face. See the L-15 for example. Lots of slotted array too also don't have IFF spread across the face, like F-16, where the IFF is embedded on top of the nose instead.

apg-68.jpg



IFF on the face is an engineering compromise. Its likely the IFF system on the J-10B was directly inherited from the J-10A and they don't want to break compatibility until an all new IFF system is introduced to replace it.

On the other hand, every, every example of canted phase array you will find in the West is an AESA.

download (16).jpegimage-47.jpgimages (13).jpegraven-es.jpg
 

latenlazy

Brigadier
Based on what? Is there any technical proof that the J-10B array is a PESA? Because of what? Internet momentum?

That diagram is clear as day mentioning a brick architecture for the -10B radar. Modules on AESA are arranged in bricks.

This is what a traditional parallel feed PESA looks like at the edge, using BARS here for the SU-30. Those coils there are the ferrite yttrium phase shifters.

View attachment 71375

In contrast the AESA consists of bricks and planks.

View attachment 71376

The -10B radar describes a 2 piece brick package on the third line. The -16 radar describes a different brick packaging design. Perhaps for better cooling?

The -10B radar description is also explicit in mentioning T/R. PESA has separate transmit and receive subarrays while in an AESA, an element is both transmit and receive.

It takes some years to develop a military radar, so the timeline around 2009 is about right. Military radars don't advance as fast as commercial and civilian equipment. Phase arrays used in telecom already use a tile based architecture (a) and they make AESA brick designs (b) look like dinosaurs.

View attachment 71377


What you see on the diagram with regards to the J-16 and J-20 radars should be more or less same as the diagrams with some up to date refinements. The J-16 radar might be using the 40nm CETIC octacore DSP while the J-20 the 28nm or 40nm CETIC DSP which is not impressive if your idea of modern is 7nm to 14nm. But again, using the stacked chip or Multi Module Chip design can go a long way of compensating for the older fab process, not to mention the larger legacy transistor sizes might be more reliable anyway. The J-10C radar should be more or less along the lines of the J-16 radar but smaller, less elements and less power. Another significant advancement in these years is whether the AESA moved from using Gallium Arsenide for its amplifiers to Gallium Nitride.
It's been long established now that the radar on J-10B (in the picture depicted) is a PESA, not an AESA.

As for JL-10, ultimately we only have rumours to go by, and the rumours have all suggested it is PESA as well.
Tam’s points gets back to something I’ve mentioned a few times before over the years. It’s possible the J-10B radar with the IFF probe is an AESA, but also if the J-10B did end up using a PESA it’s a radar we haven’t seen before. Another possibility is that the J-10B was using the radar with IFF probes and that radar was an AESA, but the J-10C received an upgraded AESA, and whoever originated the information that the J-10B used a PESA simply assumed that if the J-10C was getting a new radar that was an AESA the J-10B’s radar must have been PESA from all the earlier speculations about the IFF probes. After all, we actually never got confirmation over *how* it was determined that the J-10B was using a PESA, and this wouldn’t be the first time that in an information vacuum we backpedaled into conventional understandings built on speculations which became seen as established fact, without hard confirmation.
 

Tam

Brigadier
Registered Member
Tam’s points gets back to something I’ve mentioned a few times before over the years. It’s possible the J-10B radar with the IFF probe is an AESA, but also if the J-10B did end up using a PESA it’s a radar we haven’t seen before. Another possibility is that the J-10B was using the radar with IFF probes and that radar was an AESA, but the J-10C received an upgraded AESA, and whoever originated the information that the J-10B used a PESA simply assumed that if the J-10C was getting a new radar that was an AESA the J-10B’s radar must have been PESA from all the earlier speculations about the IFF probes. After all, we actually never got confirmation over *how* it was determined that the J-10B was using a PESA, and this wouldn’t be the first time that in an information vacuum we backpedaled into conventional understandings built on speculations which became seen as established fact, without hard confirmation.

Some guy claimed, "established", that the J-10B radar is a PESA because of the IFF dipoles across its face, similar to the IFF dipoles BARS has its on its face.

That's really poor reasoning. IFF dipoles across the face of an AESA affects the AESA no differently than a PESA because both are phase arrays. The two arrays differ in their internal architecture, not in their steering method, not in their transmit method and not in their receive method. I have not seen any other PESA with IFF dipoles across their face in fact, and even many slotted arrays don't have IFF dipoles across their face such as among many Western designs. The use

The reason for the IFF design is simple. The Chinese copied the IFF design from someone, implemented the system on their older radars, then passed on the IFF system to newer radars, even as their fighter radars evolved from parabolics to slotted arrays then to phase arrays. The old system is retained because they have not devised a newer and more efficient system due to the lack of money and resources, and because the system did work. We know the Chinese approach is conservative, they do not change what is not broken until they have figured out a way to make a more efficient system. Then at some point, they managed to create a more efficient IFF and the dipoles across the face are gone.

download (19).jpeg

Its the same argument for the dreaded pitot tube you see on the older Flankers that are not J-16s. The pitot tube is an older system that's inherited from the older Flankers and have been there since the beginning, and the J-16 got a new airspeed measuring system. While the pitot tube has some slight interference on the radar system because its on the way, it should not matter if its an AESA, PESA, slotted array, Cassegrain or Parabolic. It should have a slight interference on the radar behind regardless of the radar's internal architecture. The composition and quality of the bandpass radome should have been a stronger factor with regards to the radar's performance, but also that too is independent of the radar's internal architecture. Whether its dark, light, green or blue, the color of the radome has no bearing on the radar's internal architecture unless the radome's color is used as an identification method for a newer jet.


Me thinks its some netizens that are over analyzing things, look hungrily for clues because of the lack of information. Things would have been better if there is some more transparency. In their overthinking things they begin to make wrong connections here and there and so on.

On the L-15, I am going to take what I said back. The slotted waveslot phase array on that picture, is likely to be BARS-130 itself. So it does use ferrite phase shiters. But the feed to the phase shifters may not be using co-ax cables but an interconnecting grid, saving space and weight. The antenna on the BARS-130 is different from the BARS used on the Su-30MKI, as you can see, it uses slotted wave guides while the MKI's BARS uses patch antennas. Somewhere along other versions of BARS were using jigsaw or sawtooth antennas.

EC9in3oX4AA1a6v.jpg

BARS-130 is specifically designed for the Yak-130 jet trainer which is very similar to the Hongdu L-15. So this is what may be installed on the Hongdu L-15 itself. But the Hongdu L-15's radar lacked the IFF probes on the Russian version and that's because IFF systems are not shared internationally because the Russian IFF is for Russian planes and the Chinese IFF is for Chinese planes. For example, the Russian naval radars like Fregat that were sold to China have their IFF removed. So in this case, the Hongdu L-15 has a newer and different Chinese IFF. You don't see the one on the J-10B radar's either, and that's probably because the L-15 already has a newer IFF system than the one on the J-10B prototype (there is a possibility production J-10B batches may already have a newer IFF.)

29yqo91.jpg
 

ougoah

Brigadier
Registered Member
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Yet another step closer to viable military photon "radar"? Sooner or later Chinese, American or Russian MIC will find a way to make this operational throughout its range of sensor platforms and integrate it with the rest of their arsenal.

Hyperpower India will still be making talk about why Uttam AESA is the be all end all of sensor technology and how China is copying and stealing technology because someone somewhere might have hacked something.
 

nlalyst

Junior Member
Registered Member
The reasons why the US and the Soviet Union went with passive phase array for fighter jets, like that on the MiG-25/31 Zaslon, and AWG-9 on the F-14 Tomcat is because, one word...the Seventies. The digital tech just isn't there yet. The US tried a naval AESA on the USS Long Beach cruiser, and it failed because the concept was too advanced at that time, and the fallback led to the SPY-1 PESA. As for the Soviet Union, they used PESA for a longer period of time because of sanctions that limited their digital technology.
This is not true. AESA radars are not by definition digital. Early AESA radars that the US built and fielded in the late 70s were certainly analog. Even the AESA on the F-22 is analog.

Speaking of Long Beach, what is your source for SCANFAR being AESA? I always wondered about that, but the few sources I could find never clarified much. I've seen claims that the failed predecessor to SCANFAR, the Typhon radar, was designed as an AESA. That was in the 60s. It used a Luneberg lens for phase computation and beamforming and pointing. It had power amplifiers for each radiator:

1625861384400.png

The setup looked quite impressive, atlhough mantaining that must've been a nightmare:
1625862142400.png
But the J-10B isn't the Seventies. It is by then, the 2000s. China has already implemented its first military applied and accepted AESA at the turn of the decade, the SLC-2, an artillery finder radar. Its first naval AESA, the Type 346, is already being developed for many years, and the design is already finalized before the first Type 052C was laid down. China has no lack of access to digital technology; it is knee deep in it. By the 2000s, its already a major PC manufacturer. You look at other fighter PESA like the first version of RBE2 for the Rafale and that project started in the late eighties. But by far, fighters that started with a slotted array, switched to an AESA on later versions, without going through a PESA stage. The reasons why NRIET never went PESA and went straight to an AESA for the 052C, is probably why you don't see any PESA on the PLAAF, and every airborne phase array in PLAAF service is likely to be an AESA is because NRIET is also the company that does these airborne radars --- including for the J-10, J-11, and J-20. The company started developing AESA early and its built a strong foundation of clear competence on this. Its not likely to develop a PESA already knowing its a dead end technology branch, a deviation from its core competence, would waste valuable development resources and has inherent disadvantages. I don't know if NRIET is behind the JL-10 trainer's radar, but a trainer doesn't need a heavy radar on its nose, and it doesn't need an expensive and powerful radar. Its most likely a slotted array.
No PESA on the PLAAF? First time I hear this.
 
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latenlazy

Brigadier
No PESA on the PLAAF? First time I hear this.
The J-10B *may* have used a PESA, or its radar may have been an earlier AESA that then got swapped out for another AESA in the J-10C. We never did figure out the identity of the J-10B's radar. The rumor that it was a PESA came from the radar having IFF dipoles, and the "confirmation" for that seemed to have been a crowdsourced retroactive determination from the J-10C being shown with a different radar. To my knowledge no one with credible authority ever confirmed this retroactive determination.
 

Inst

Captain
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Yet another step closer to viable military photon "radar"? Sooner or later Chinese, American or Russian MIC will find a way to make this operational throughout its range of sensor platforms and integrate it with the rest of their arsenal.

Hyperpower India will still be making talk about why Uttam AESA is the be all end all of sensor technology and how China is copying and stealing technology because someone somewhere might have hacked something.
There are many very smart Indians who have a fine grasp of reality. There, unfortunately, are just way more bhakts and hypernationalists who drive the former category crazy and contribute to an overwhelming Indian urge to emigrate.
 

Inst

Captain
Some guy claimed, "established", that the J-10B radar is a PESA because of the IFF dipoles across its face, similar to the IFF dipoles BARS has its on its face.

That's really poor reasoning. IFF dipoles across the face of an AESA affects the AESA no differently than a PESA because both are phase arrays. The two arrays differ in their internal architecture, not in their steering method, not in their transmit method and not in their receive method. I have not seen any other PESA with IFF dipoles across their face in fact, and even many slotted arrays don't have IFF dipoles across their face such as among many Western designs. The use

The reason for the IFF design is simple. The Chinese copied the IFF design from someone, implemented the system on their older radars, then passed on the IFF system to newer radars, even as their fighter radars evolved from parabolics to slotted arrays then to phase arrays. The old system is retained because they have not devised a newer and more efficient system due to the lack of money and resources, and because the system did work. We know the Chinese approach is conservative, they do not change what is not broken until they have figured out a way to make a more efficient system. Then at some point, they managed to create a more efficient IFF and the dipoles across the face are gone.

View attachment 71425

Its the same argument for the dreaded pitot tube you see on the older Flankers that are not J-16s. The pitot tube is an older system that's inherited from the older Flankers and have been there since the beginning, and the J-16 got a new airspeed measuring system. While the pitot tube has some slight interference on the radar system because its on the way, it should not matter if its an AESA, PESA, slotted array, Cassegrain or Parabolic. It should have a slight interference on the radar behind regardless of the radar's internal architecture. The composition and quality of the bandpass radome should have been a stronger factor with regards to the radar's performance, but also that too is independent of the radar's internal architecture. Whether its dark, light, green or blue, the color of the radome has no bearing on the radar's internal architecture unless the radome's color is used as an identification method for a newer jet.


Me thinks its some netizens that are over analyzing things, look hungrily for clues because of the lack of information. Things would have been better if there is some more transparency. In their overthinking things they begin to make wrong connections here and there and so on.

On the L-15, I am going to take what I said back. The slotted waveslot phase array on that picture, is likely to be BARS-130 itself. So it does use ferrite phase shiters. But the feed to the phase shifters may not be using co-ax cables but an interconnecting grid, saving space and weight. The antenna on the BARS-130 is different from the BARS used on the Su-30MKI, as you can see, it uses slotted wave guides while the MKI's BARS uses patch antennas. Somewhere along other versions of BARS were using jigsaw or sawtooth antennas.

View attachment 71426

BARS-130 is specifically designed for the Yak-130 jet trainer which is very similar to the Hongdu L-15. So this is what may be installed on the Hongdu L-15 itself. But the Hongdu L-15's radar lacked the IFF probes on the Russian version and that's because IFF systems are not shared internationally because the Russian IFF is for Russian planes and the Chinese IFF is for Chinese planes. For example, the Russian naval radars like Fregat that were sold to China have their IFF removed. So in this case, the Hongdu L-15 has a newer and different Chinese IFF. You don't see the one on the J-10B radar's either, and that's probably because the L-15 already has a newer IFF system than the one on the J-10B prototype (there is a possibility production J-10B batches may already have a newer IFF.)

View attachment 71427


===

The counterargument is that AESA is frequency agile in a way that PESA is not, since signals are generated by T/R modules under computer control, instead of being generated by a single magnetron and being phase-shifted.

In other words, AESA doesn't need IFF dipoles because it can be done via software instead of having dedicated dipoles on the face of the array. The counter example would be the F-16 with IFF dipoles built onto the sides of the radar, but the implementation, first, resembles legacy features (i.e, the F-16 had IFF systems that didn't rely on the dipole before the AESA was installed, and these weren't removed), and second, the implementation (with IFF dipoles to the side, not within the AESA) is different.

I think it's most likely that the J-10B went through a PESA phase, before transitioning off to AESA.
 

latenlazy

Brigadier
===

The counterargument is that AESA is frequency agile in a way that PESA is not, since signals are generated by T/R modules under computer control, instead of being generated by a single magnetron and being phase-shifted.

In other words, AESA doesn't need IFF dipoles because it can be done via software instead of having dedicated dipoles on the face of the array. The counter example would be the F-16 with IFF dipoles built onto the sides of the radar, but the implementation, first, resembles legacy features (i.e, the F-16 had IFF systems that didn't rely on the dipole before the AESA was installed, and these weren't removed), and second, the implementation (with IFF dipoles to the side, not within the AESA) is different.

I think it's most likely that the J-10B went through a PESA phase, before transitioning off to AESA.
No amount of software can change the transmitter band your hardware is configured for. IFF and fighter radars work on completely different bands. You still need dedicated antennas for the IFF bands independent of the AESA bands. That’s what those dipoles are for.

In fighters where you don’t see IFF dipoles in the radar, that’s often because the IFF transceiver and antennas are a completely independent subsystem, rather than integrated. I believe this modularized implementation became more common as transceivers became smaller and more efficient, so that you could depend on more distributed power sources rather than bandwagon off the radar’s.
 
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