Chinese AEGIS capability and comparison


Max Demian

Junior Member
Registered Member
Hi everyone. I would like to collect in this thread all the information we have on the Chinese "AEGIS", including radar systems, SAMs, data links, etc.

I will start with the overview of the core system, the Type 346 radar.

This is suspected to be a S-band AESA radar, with an octagonal antenna of about 4m diameter and antenna aperture of about 12.5m2. The AESA is built out of quad TRMs, with each quad capable of 100W peak RF power. Total number of quads is estimated to be 1250, for a total of 5000 T/R elements and 125kW peak RF per antenna. Antennae are air-cooled. Max instrumented range is about 450km. The S-band antenna is sandwiched between two C-band arrays. The function of the C-band arrays is to provide uplink/downlink communication with the principle weapon of the Chinese AEGIS: HHQ-9. Only known photo of the S-band/C-band antenna, taken from a type 052C being fitted out. Authenticity of this photo has not been verified.
1603525899568.png
Fan-made sketch of antennae layout:
1603526534210.png

Type 052D destroyers were built with what appears to be an updated version of the radar, dubbed Type 346A. The antennae are slightly larger, and the external shielding has a more square-like shape. This radar uses liquid cooling, which implies that the power output went up. The C-band missile uplink/downlink antennae are retained. Because of the higher topside weight of the larger, heavier radar and the enlarged VLS, the Type 052D has a 1m greater draft than 052C, which slightly reduces the radar horizon and increases susceptibility to water spray. A nice comparison photo:
1603528554178.png

The principal SAM of Chinese AEGIS is HHQ-9. The missile body appears to be ported from the land HQ-9 system, but the guidance system was a new design: it employs an active radar seeker. Range estimates for the first version on board Type 052C were anywhere between 90km to 150km. By virtue of using ARH the firepower of Type 052C and Type 052D ships is substantial: the number of targets that can be engaged simultaneously is only limited by the number of missiles onboard. ARH capability makes it theoretically possible to engage beyond the horizon targets. The fact that PLA Navy deployed an ARH only SAM in the early 2000s was quite a surprise. Latest versions of HHQ-9 are credited with a range of 200+ km and have secondary IR seekers. The latter is likely a backup in case the ARH mode is defeated by ECM/chaff/stealth.

Radars and SAMs are only a part of what makes AEGIS. The other equally important elements are data links and networking software. The American AEGIS makes it possible to fuse data from other ships and aircraft in real-time and present it on a single display onboard each AEGIS ship. The platform that fires a missile need not be the one that detected the target. It needs not even to track the target. Needless to say, this was revolutionary capability in the 80s.

Perhaps someone can fill in the details on Chinese data link and networking capabilities?

Another unknown is BMD. So far no indication that this capability is present has surfaced?
 

Max Demian

Junior Member
Registered Member
Is the ARH on the early HHQ-9s fully autonomous or is it command guided all the way to target?

Command guidance could explain the need for adopting C-band for missile uplink/downlink, due to higher data bandwidth requirements. X-band would be even better, but it suffers from atmospheric absorption at long ranges.
 

Max Demian

Junior Member
Registered Member
What is the risk of relying solely on ARH guidance without SARH backup? How would it perform against stealth platforms compared to SARH?

There is a school of thought in the USN that the small, battery powered ARH missile seeker is not robust enough to fight through an ECM heavy environment. That's why all currently built DDG-51 FLIIA and FLIII destroyers, and also the JMSDF new Maya class, retain the AN/SPG-62 2.3m diameter high-power X-band illuminators, which are slaved to the S-band SPY-1 radar.
 

Tam

Colonel
Registered Member
Hi everyone. I would like to collect in this thread all the information we have on the Chinese "AEGIS", including radar systems, SAMs, data links, etc.

I will start with the overview of the core system, the Type 346 radar.

This is suspected to be a S-band AESA radar, with an octagonal antenna of about 4m diameter and antenna aperture of about 12.5m2. The AESA is built out of quad TRMs, with each quad capable of 100W peak RF power. Total number of quads is estimated to be 1250, for a total of 5000 T/R elements and 125kW peak RF per antenna. Antennae are air-cooled. Max instrumented range is about 450km.

I tend to think now each channel is capable of peak 100W rather than the module based on the descriptions of the Yonlit modules. Each quad has its own HPA and LNA per channel and four elements controlled by a single base band and beam forming processor.

The S-band antenna is sandwiched between two C-band arrays. The function of the C-band arrays is to provide uplink/downlink communication with the principle weapon of the Chinese AEGIS: HHQ-9. Only known photo of the S-band/C-band antenna, taken from a type 052C being fitted out. Authenticity of this photo has not been verified.
View attachment 64862
Fan-made sketch of antennae layout:
View attachment 64863

I am beginning to think that the top bar is more likely an IFF, and the bottom bar might be used as a sidelobe canceler. The communication arrays might be the four small squares situated on each corner of the array. Take the inspiration from the MPQ-53's design, where the IFF bar is the bar beneath the array, and the TVM is the small array on the bottom right.

img4231.jpg

On the HT-233 radar, the top bar is the IFF, but what are the three large squares on the bottom? There is only one main feed to the array so I doubt the three auxiliary panels are radars.

unnamed (10).jpg

However, the earlier design of the array is more interesting as you see the two smaller circular arrays on the corners. But again, only one main feed to the array. The two small circular arrays at the bottom corners could be for TVM. The array has a bar on top and that should be for the IFF.

CASIC-SJ-231-Engagement-Radar-KS-1A-1S.jpg


If you take the CEAFAR and CEAMOUNT radar as examples, the CEAMOUNT illuminators are shaped as small rectangles and is longer on the vertical axis.

anzac.png

So the question is whether illuminators similar to CEAMOUNT there can be fit on the corners of the array.

Type 052D destroyers were built with what appears to be an updated version of the radar, dubbed Type 346A. The antennae are slightly larger, and the external shielding has a more square-like shape.

Square like shape because the array is equal sized on both axis. The IFF is then moved from the array to a bar on top of the bridge.

This radar uses liquid cooling, which implies that the power output went up. The C-band missile uplink/downlink antennae are retained. Because of the higher topside weight of the larger, heavier radar and the enlarged VLS, the Type 052D has a 1m greater draft than 052C, which slightly reduces the radar horizon and increases susceptibility to water spray. A nice comparison photo:
View attachment 64864

The principal SAM of Chinese AEGIS is HHQ-9. The missile body appears to be ported from the land HQ-9 system, but the guidance system was a new design: it employs an active radar seeker.

I am leaning the active radar seeker isn't new at all, that the land based version of the missile had it all along in the first place, at least in its operational form. During development phase it could be something else. The description of composite suggests to me the missile is TVM or command guided at its inertial and midphase, with the terminal phase being active radar seeking.

FD-2000_Missile_SAM_4.jpg


Range estimates for the first version on board Type 052C were anywhere between 90km to 150km. By virtue of using ARH the firepower of Type 052C and Type 052D ships is substantial: the number of targets that can be engaged simultaneously is only limited by the number of missiles onboard. ARH capability makes it theoretically possible to engage beyond the horizon targets. The fact that PLA Navy deployed an ARH only SAM in the early 2000s was quite a surprise. Latest versions of HHQ-9 are credited with a range of 200+ km and have secondary IR seekers. The latter is likely a backup in case the ARH mode is defeated by ECM/chaff/stealth.

ARH is still limited by one thing, and that is the availability of channels the system has for the datalinks. If the system has 16 channels, then you are maxed at 16 missiles, unless you forego the links, which is useful for engaging more targets at close range but at the expense of range. This means the missile is given all information about its target right before its launch with no datalink update.

Radars and SAMs are only a part of what makes AEGIS. The other equally important elements are data links and networking software. The American AEGIS makes it possible to fuse data from other ships and aircraft in real-time and present it on a single display onboard each AEGIS ship. The platform that fires a missile need not be the one that detected the target. It needs not even to track the target. Needless to say, this was revolutionary capability in the 80s.

Little is known but it does not appear PLAN has developed the same level of CEC capability until recently. USN has gone three generations with its CEC arrays, from USG-1, to -2, and then to -3, which consists of four small phase arrays. USG-3 is part of the AEGIS Baseline 9 update.

But recently we have seen PLAN warships popping up with flat panel domes, which keeps a gyrostabilized phase array inside. The range of uses for such arrays are wide, as they can be used as SATCOM, or communication with drones, or as a CEC datalink with aircraft or helicopters. But in the Liaoning, Shandong, the Type 055s and the 075s, there are four small phase arrays high on top of their masts, which is very likely to be CEC. The fact that the four ship classes don't have the small flat panel domes that are retrofitted to the other ship classes is a good indication both have the same purpose and the phase array domes are rendered redundant by the four phase arrays.

One concern is that these domes are set low, on top of hangers or the bridge, which limits their radar horizon and therefore the distance between ships if its a direct ship to ship communication (052D and below). However, the four arrays set on the Liaoning, Shandong, Type 075 and 055 are set high in their masts so ship to ship data exchange with these ships can occur at a greater distance. I think the 055 can act as a node for smaller ships around her.

Illustration of flat panel SATCOM. This one is for commercial use but similar in design to the ones popping up all over PLAN ships.
unnamed (11).jpg


Perhaps someone can fill in the details on Chinese data link and networking capabilities?

Due to the good number of SATCOMs PLAN warships have, its a good bet they heavily rely on satellite communications between ships to allow for data exchange over the horizon and OTH target engagement with antiship missiles.

Another unknown is BMD. So far no indication that this capability is present has surfaced?

There is some comment about limited BMD. This likely refers to smaller ballistic missiles on a local area, so close range.
 
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Tam

Colonel
Registered Member
Is the ARH on the early HHQ-9s fully autonomous or is it command guided all the way to target?

Command guidance could explain the need for adopting C-band for missile uplink/downlink, due to higher data bandwidth requirements. X-band would be even better, but it suffers from atmospheric absorption at long ranges.

Based on the land system, the ARH on the HHQ-9 is likely to be terminal phase, unless its fired at say, targets around 30 to 50km. At these ranges, the missile will have to be fired blind, with the inertial navigation system already set to where the expected target is going to be.

At longer ranges you are going to need guidance for the midphase, and you are going to have to rely on command guidance.

Early 5V55 missiles used with the S-300 complex are command guided all the way to the target. Do note that the phase array used to fire control these missiles are all in X-band, and you can't get that level of precision with an S-band radar, and so you will need the active seeker to complete the final leg of the journey.
 

Tam

Colonel
Registered Member
What is the risk of relying solely on ARH guidance without SARH backup? How would it perform against stealth platforms compared to SARH?

The problem I see using SARH as a midphase guidance system is that it warns the target way too early, and allows the target to do countermeasures. Any ESM or RWR can easily pick it up and ID the waveform. Its a good bet if you pick up a continuous wave X-band, its time to drop the countermeasures or rush home.

The neat thing about ARH is that you can guide the missile in its midphase via datalink update while the radar is in its search mode, or track while scan, like in a low PRF S-band. The target knows its already detected, but its ESM or RWR tells the operator that the radar is a search radar or is in search mode, which leaves the operator pilot to guess whether a missile is fired or not. When the missile goes live, and the RWR warns, it might already be too late. The more late the missile seeker goes live, allowing the missile to "creep" into the target, the greater the kill probability.

There is a school of thought in the USN that the small, battery powered ARH missile seeker is not robust enough to fight through an ECM heavy environment. That's why all currently built DDG-51 FLIIA and FLIII destroyers, and also the JMSDF new Maya class, retain the AN/SPG-62 2.3m diameter high-power X-band illuminators, which are slaved to the S-band SPY-1 radar.

That was then, this is now.

First of all, the HQ-9 is not small. This is a 1300kg weighing missile and is about 6.8 meters long. The SM-2 Standard is about 700kg and the SM-6 is about 1500kg. A Tomahawk is about 1100kg. So this missile is heavier than a Tomahawk and is way bigger than many antiship missiles, such as the YJ-83, which is about 700kg, and has an active radar seeker. The ARH powered AIM-54 Phoenix is about 470kg.

The USAF certainly don't subscribe to this, given AMRAAM.

Whatever that school of thought is, it doesn't apply to the Europeans with their Asters, or the Russians with their Reduts.

The problem of SARH is that the farther the beam gets, the weaker it gets. So at long ranges, SARH might be more vulnerable to ECM. Another problem with SARH is that at longer ranges, lets say at 100km or so, the beamwidth would be like over a kilometer wide, and if the target is towing a decoy or dropped a decoy, those decoys would be illuminated within the beam.
 
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gelgoog

Senior Member
Registered Member
...
Perhaps someone can fill in the details on Chinese data link and networking capabilities?

Another unknown is BMD. So far no indication that this capability is present has surfaced?

The Chinese Navy has developed its own digital datalink. They had access to Western technology of the late 1980s that was used in the original Type 052 class of two ships. So they should be pretty familiar with how Western systems are. Not to mention that the datalinks have written specifications available. How else would different NATO navies interoperate?
You have to assume the Chinese Navy ships are able to have a full view of the dataspace including merging together radar and position data for air targets, ships, and missiles, etc.

There are reports of anti-ballistic missile tests being conducted with the HQ-9 system. So it wouldn't be surprising if the Chinese Aegis also has some ABM capability.
 

Max Demian

Junior Member
Registered Member
I tend to think now each channel is capable of peak 100W rather than the module based on the descriptions of the Yonlit modules. Each quad has its own HPA and LNA per channel and four elements controlled by a single base band and beam forming processor.
The sources for the quad configuration are for the first iteration of the radar installed on Type 052C. I have not found anything on the follow up variants.

Tam said:
I am beginning to think that the top bar is more likely an IFF, and the bottom bar might be used as a sidelobe canceler. The communication arrays might be the four small squares situated on each corner of the array. Take the inspiration from the MPQ-53's design, where the IFF bar is the bar beneath the array, and the TVM is the small array on the bottom right.
Maybe, but I found no reference of the sidelobe canceler in the Chinese source. However, it does appear that only one of the horizontal bars would've been used for communication with HHQ-9s:
Chinese Academician in translation said:
After I returned to my room, I estimated it in my heart, and then asked Chen Hongyuan for a piece of paper (he tore a piece of paper from a practice book and gave it to me). An S-band octagonal array with a height of 4 meters and a width of 4 meters is drawn on it, and a 0.2-meter-wide and 4-meter-long strip is drawn on the upper and lower sides of the S array. Both strips can be used to install C -Band response antenna, which one to choose depends on whether it is blocked. Assuming that the upper strip is used, the antenna area is about 0.8 square meters. This is more than 2.5 times larger than the area of the C-band response antenna (about 0.6 meters in diameter and only about 0.3 square meters in area) placed in the lower right corner of the S-band octagonal array. If the center of the S-band octagonal array can be allowed to move up or down by 0.1 meters, the area of the C-band antenna can still be large. In this way, the problem of weak reception of the beacon signal on the HH-9 missile is solved. As the area of the C antenna increases, the gain will also increase, so weak signals can naturally be received.

The same source mentions that the initial design settled on an array of 4768 T/R elements. Quad architecture was adopted because it reduces weight and volume, and each quad was aiming for almost 100W peak power.

Some other interesting details about the S-band vs C-band wars:
Chinese Academician in translation said:
Faced with the profound design skills of 14 multi-functional phased array radars, the Second Academy of the Ministry of Aerospace avoided the basic point of multi-functional radars and used their advantageous conditions for developing H-9 missiles, and proposed by sudden attack:

1) The strength of the beacon response signal of the HH-9 missile has been weakened (much less than the strength of the original radar plan demonstration index. The reason is to improve the concealment);

2) The required guidance distance of the HH-9 missile has become longer (a few tens of kilometers have been added at once, which is much larger than the distance of the original radar scheme demonstration index);

3) The reflection cross-sectional area of the tail and side of the HH-9 missile has become smaller (smaller than the reflection cross-sectional area of the missile head, and much smaller than the reflection cross-sectional area of the original radar plan demonstration index).

Therefore, the S-band main front of the 14th Research Institute plus a small C-band HH-9 beacon response front can not meet the missile's target attack guidance mission. Only the 23rd C-band phased array scheme is adopted.

At the same time, they also attacked that the S-band has a longer wavelength than the C-band, so the low-angle tracking performance is not as good as the C-band.

This part confirms the missile has a final active homing stage and discusses some further on the issues related to midcourse guidance. But does it refute the SAGG conjecture?
Chinese Academician in translation said:
Long-range missile strikes are divided into two stages, passive guidance and active guidance. In the passive guidance section, after the missile is launched, it is tracked by radar and sends correction commands to guide the missile to the target. The active guidance section turns on the active homing function after the missile approaches the target to automatically seek and hit the target. The purpose of our investigation is to know how long the missile can be actively guided? What is the power and sensitivity of the response antenna on the missile? And what is the orbit of the missile launch section? The signal receiving direction of the response antenna on the missile, the accuracy requirements of the passive guidance terminal missile and the target, and the actual data of the reflection cross-sectional area of the missile's head, tail, and sides in various directions, etc.

This part discusses some of the deficiencies in the design: low placement of the arrays and the fragile cooling solution. It also confirms that the array is not of uniform density.
Chinese Academician in translation said:
The two points of dissatisfaction are:

1) The wall of the 052C equipped with phased array is not high enough. Although the front is also installed on a 45-degree survey surface, the railing of the ship will have an impact on low angles, especially on the central axis of the ship, which has a lot of equipment and has a greater impact on the low angle capability of the radar;

2) Adopt the reflux ventilation method of the radome. There are two problems with this scheme: one big and one small. The big problem is that in case of a war, the radome makes a big hole (the small hole still has little effect), then the air duct is completely destroyed, even if the active array is not broken (or partly broken, but it can still work), because The front became hot and had to stop working at that time. The small problem is that there are the most T/R components in the middle of the front. In order to increase the static pressure and ventilation wind, the radome must be bulged in the middle. In addition to being unsightly, it also increases the probability of the radome being attacked.

On the final design having more than 5000 T/R elements and how it helps with tracking the HHQ-9 missiles. At one point he mentioned the radar system had to consume 30% of its budget to track 8 HHQ-9 missiles.
Chinese Academician in translation said:
Seriously, comprehensively, and carefully checked the plan and made the necessary changes. The most important one is that I want to increase the number of antenna element points (that is, the number of T/R components) of each array from 4768 points in the original plan to more than 5000 points. The reason why I have to make such a big change at this last moment is:

1) After nearly two years of continuous efforts, the length of T/R modules has been reduced from the original 45cm to 40cm, and the structural materials of the modules have also been changed to lighter materials, which significantly reduces the weight. Therefore, it is now possible to increase the number of T/R components within the limit of the front weight not exceeding 4 tons;

2) Increasing the number of T/R components on the front can increase the radar signal power (especially the monopulse signal power), which means that the energy resources of the radar increase. This can resolve the unreasonable phenomenon that the original HH-9 reflection cross-sectional area is so small that it occupies a large proportion of radar resources in order to track HH-9, and sacrifices search distance and other special functions.

3) When the number of T/R components increases to more than 5000, the search distance increases. It can ensure that the entire coverage area is greater than 375 kilometers, and the central area is greater than 400 kilometers. This will greatly increase the combat capability and survivability of ships from the perspective that modern warfare is an out-of-sight warfare;

4) The most important point is that increasing the power of the single pulse signal can significantly improve the single pulse angle and ranging accuracy of the radar. Because of the many factors that affect accuracy, the strength of the signal-to-noise ratio is one of the most important factors that affect accuracy. The radar signal power is strong, the signal-to-noise ratio is large, so that the single pulse angle measurement accuracy is high. I especially emphasize the single pulse here because the ship is shaking at sea. The pulse accumulation method is used to improve the signal-to-noise ratio. As far as the ship is concerned, I have doubts. Furthermore, if the target appears at the downward sweep angle where two fronts are intersected, the radar beam being tracked has become very fat (this is a unique phenomenon of phase-scan radar), and it is difficult to lock the target with one front. Single pulse power will become the absolute key to hitting the target.
 
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Max Demian

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Talking about the TRM quads. It is not clear whether the 100W peak is radiated power or power delivered to the antenna. Assuming it is RF power, then we are looking at max 25W average power per quad. Assuming 5000 T/R elements, we are looking at about 31.25kW average radiated RF per radar face, which is pretty good for an AESA and comparable to first generation SPY-1s.
 

Tam

Colonel
Registered Member
That's some interesting stuff to read although the Chinese to English translation hits me in the face.


The sources for the quad configuration are for the first iteration of the radar installed on Type 052C. I have not found anything on the follow up variants.


Maybe, but I found no reference of the sidelobe canceler in the Chinese source. However, it does appear that only one of the horizontal bars would've been used for communication with HHQ-9s:

It can be that the top bar might be used as an IFF, and maybe the lower bar might be used for missile communication,


The same source mentions that the initial design settled on an array of 4768 T/R elements. Quad architecture was adopted because it reduces weight and volume, and each quad was aiming for almost 100W peak power.

Some other interesting details about the S-band vs C-band wars:


This part confirms the missile has a final active homing stage and discusses some further on the issues related to midcourse guidance. But does it refute the SAGG conjecture?


This part discusses some of the deficiencies in the design: low placement of the arrays and the fragile cooling solution. It also confirms that the array is not of uniform density.


On the final design having more than 5000 T/R elements and how it helps with tracking the HHQ-9 missiles. At one point he mentioned the radar system had to consume 30% of its budget to track 8 HHQ-9 missiles.

The radar is definitely tracking both missile and target, and that should be expected with command guidance But it does not say anything about the seeker aiding during midphase.

The curved face used in the 052C risks increasing the ship's radar cross section. Switching to the flat face in the later version was obvious.
 

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