Naval missile guidance thread - SAM systems

[Max Demian]

The real question is that even if you are able to use C-band for guidance, what makes you think its better to use than X-band? The case is really why use C-band when X-band is superior for this purpose. The HQ-9 seeker is still fairly small and X-band will still give you better angular accuracy. It should not be any bigger than the S-300 missiles like the 48N6 and 5V55 that it is very similar to, and it should be slightly smaller. Yet the 48N6 and 5V55 are both guided on X-band.

AN/MPQ-53 is intended to be able to operate as a self contained all in one unit.

The C in C-band stands for "compromise". As you answered your own question , it enables a MFR with search/track/engage capability.

Concerning target engagement. As you pointed out, TVM is not without advantages. It is a multistatic radar system. The fire control system gets to process two reflections from the target: I suspect this is enough to overcome the weaker angular resolution compared to X-band.

Coming back to the question of Type 346 and HHQ-9.

The fact that everything points to HHQ-9 being derived from HQ-9, a C-band TVM guided missile, is what led me hypothesize that HHQ-9 introduced on Type 052C maintained the same guidance system. This would most elegantly be supported by a MFR radar with search/track/engage and TVM missile quidance, just like what is provided by Patriot and HQ-9 SAM systems from which it is ostensibly derived. Let's call this hypothesis A.

As far as I know, there is no shot of the Type 346 phase array. There is however that of the Type 346A on 052D, showing two narrow strips at the upper and lower edge of the array.

One hypothesis is that these are C-band arrays sandwiched around the central S-band array. Given their geometry, it is unlikely that these would serve an illumination purpose. Rather, it seems that they may be used for high data rate communication with HHQ-9s. This would be consistent with TVM. But in absence of any other candidate for an illumination radar we are lead to conclude that HHQ-9s on 052D must have some form of autonomous guidance in the terminal phase. Let's call this hypothesis B1.

Another hypothesis is that the two strips are an extension of the same S-band array. The communication with the missiles would then be carried out in S-band, like it is on SPY-1. Or that function may be fulfilled by the antennae that sit on top of the superstructure, above the Type 346 panels. Let's call this hypothesis B2.

In either of hypothesis B, the HHQ-9s have autonomous terminal guidance. This could be ARH or IR.

 

[Tam]

The C in C-band stands for "compromise". As you answered your own question , it enables a MFR with search/track/engage capability.

Concerning target engagement. As you pointed out, TVM is not without advantages. It is a multistatic radar system. The fire control system gets to process two reflections from the target: I suspect this is enough to overcome the weaker angular resolution compared to X-band.

Coming back to the question of Type 346 and HHQ-9.

The fact that everything points to HHQ-9 being derived from HQ-9, a C-band TVM guided missile, is what led me hypothesize that HHQ-9 introduced on Type 052C maintained the same guidance system. This would most elegantly be supported by a MFR radar with search/track/engage and TVM missile quidance, just like what is provided by Patriot and HQ-9 SAM systems from which it is ostensibly derived. Let's call this hypothesis A.

As far as I know, there is no shot of the Type 346 phase array. There is however that of the Type 346A on 052D, showing two narrow strips at the upper and lower edge of the array.

One hypothesis is that these are C-band arrays sandwiched around the central S-band array. Given their geometry, it is unlikely that these would serve an illumination purpose. Rather, it seems that they may be used for high data rate communication with HHQ-9s. This would be consistent with TVM. But in absence of any other candidate for an illumination radar we are lead to conclude that HHQ-9s on 052D must have some form of autonomous guidance in the terminal phase. Let's call this hypothesis B1.

Another hypothesis is that the two strips are an extension of the same S-band array. The communication with the missiles would then be carried out in S-band, like it is on SPY-1. Or that function may be fulfilled by the antennae that sit on top of the superstructure, above the Type 346 panels. Let's call this hypothesis B2.

In either of hypothesis B, the HHQ-9s have autonomous terminal guidance. This could be ARH or IR.

That's about it.

I should add, that it is not clear that it is a fact that the land based HQ-9 is a TVM guided missile --- there is actually no official Chinese documents pointing to that. It is assumed that it is TVM because of its resemblance to the Russian 5V55 missile. Which when you are facing the lack of official declaration, might be the most logical way to assume what the missile is. However, there is an official disclosure based on the FD2000 export brochure that it is active radar homing.

Also, communication to the Standard missile occurs through a data link on top of the Burke's mast. It is the white thing on top of the mast, above the IFF ring. You can't use a PESA for communicating with a missile when its already a radar. The PESA is connected to only one big transmission amplifier unit, for communication it would require a a small separate amplifier to generate a signal separately. VVV




In the case of a communication unit embedded on the bottom or on the corners of a PESA panel like the 30N6E, MPQ-53 or HT-233, the communication units would have their own amplifiers that is not shared with the main PESA. As independent units, they would have their own frequency and generate their own waveforms. The horn feed only supplies the signal to the main circular or octagonal array. There is no space for such units to be placed with the SPY-1 array.

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[Max Demian]

Also, communication to the Standard missile occurs through a data link on top of the Burke's mast. It is the white thing on top of the mast, above the IFF ring. You can't use a PESA for communicating with a missile when its already a radar. The PESA is connected to only one big transmission amplifier unit, for communication it would require a a small separate amplifier to generate a signal separately.

Can you give me a source on this?

Several of my sources clearly contradict what you are saying.

"The AN/SPY-1 radar performs missile and target tracking and also serves as the shipboard data link transceiver. ", Standard Missile: Guidance System Development; Witte and Mcdonald

"The AEGIS uplink, transmitted by the AN/SPY-1 radar to SM or ESSM, is in the S-band ... In the AEGIS system, the missile always responds to an uplink with a downlink transmission. The downlink, also at S-band, uses pulse position modulation and sends back missile status information.", Missile Communication Links, Clifton E. Cole Jr.

 

[Tam]

Can you give me a source on this?

Several of my sources clearly contradict what you are saying.

"The AN/SPY-1 radar performs missile and target tracking and also serves as the shipboard data link transceiver. ", Standard Missile: Guidance System Development; Witte and Mcdonald

"The AEGIS uplink, transmitted by the AN/SPY-1 radar to SM or ESSM, is in the S-band ... In the AEGIS system, the missile always responds to an uplink with a downlink transmission. The downlink, also at S-band, uses pulse position modulation and sends back missile status information.", Missile Communication Links, Clifton E. Cole Jr.

Do you want to explain how that would work with a PESA? Remember in a PESA you only have one amp, one signal and waveform generator, and that should be busy doing the PRF for the main arrays. The waveform of radar vs. telecommunications don't look alike. How do you suppose ships that don't have the SPY-1 use the Standard and ESSM missile then?

 

[Max Demian]

Do you want to explain how that would work with a PESA? Remember in a PESA you only have one amp, one signal and waveform generator, and that should be busy doing the PRF for the main arrays. The waveform of radar vs. telecommunications don't look alike.

Come on Tam. I gave you the sources. You could at least provide me with a source that claims otherwise.

How do you suppose ships that don't have the SPY-1 use the Standard and ESSM missile then?

If you bothered to read the sources I provided, you would've found the answer. There are AEGIS configured missiles capable of uplink and downlink (S-band) and then there are 2T link configured capable of uplink only in X-band (used by Dutch, German, Korean, etc navies). However, the 2T link data rate is more than 1000 times lower than the AEGIS link.

 

[Max Demian]

There is also the X-band P3I link designed for AN/SPY-3.

 

[Tam]

Come on Tam. I gave you the sources. You could at least provide me with a source that claims otherwise.

Yes, but can you still explain exactly how that can be done? A single PESA transmitter does not multitask. If its an AESA its possible because you can have a small set of elements doing something completely different from the rest, and because each has its own independent transmitter, it can be used to create its own waveforms for communication while the rest do the radar job.

If you want to use the main array for communication, and given that the SPY-1 doesn't have a dedicated row of elements as you can see from the picture, how do you expect to do it while the radar is busy scanning and tracking targets? Unlike AESA, the PESA does not have the ability to partition into multiple beams, or create different waveforms for different elements.

The only way I can think of doing this, is that while two of the arrays are scanning and tracking, the other two arrays are communicating using the entire array. And then the job is alternated among the array pairs. However, you still have an issue of a single PESA transmitter serving all four arrays that still has to work 100% of the time. You will have to set aside some of the elements with their own transmitter, but you can risk interference from the main array, if the communicating elements are right in the array itself and not separated by a short distance. You would have to not use the array during its missile communication-transmission phase, then switch back to its normal PRF scanning and tracking mode.

If you bothered to read the sources I provided, you would've found the answer. There are AEGIS configured missiles capable of uplink and downlink (S-band) and then there are 2T link configured capable of uplink only in X-band (used by Dutch, German, Korean, etc navies). However, the 2T link data rate is more than 1000 times lower than the AEGIS link.

Yes, but the Dutch and German ships have an AESA, but the Korean ships do not.

I'm sure the white dome (N-AS-267) is a universal datalink, though I am not sure if its for the Standards or for the helicopters or both. The same dome appears in all ships that can fire the Standard and ESSM missile, including the Japanese ones, the German and Dutch frigates and so on, but it is absent in all Aster firing ships.

 

[Max Demian]

Yes, but can you still explain exactly how that can be done? A single PESA transmitter does not multitask. If its an AESA its possible because you can have a small set of elements doing something completely different from the rest, and because each has its own independent transmitter, it can be used to create its own waveforms for communication while the rest do the radar job.

If you want to use the main array for communication, and given that the SPY-1 doesn't have a dedicated row of elements as you can see from the picture, how do you expect to do it while the radar is busy scanning and tracking targets? Unlike AESA, the PESA does not have the ability to partition into multiple beams, or create different waveforms for different elements.

Sorry, not my field of expertise.

According to Wikipedia (quoting

)
SPY-1 doesn't have one, but eight transmitters each hooked to 4 CFAs. Furthermore, the phase array is subdivided into over a 100 modules. This would seem to indicate that the radar may be capable of multi beaming.

 

[Tam]

Sorry, not my field of expertise.

According to Wikipedia (quoting

)
SPY-1 doesn't have one, but eight transmitters each hooked to 4 CFAs. Furthermore, the phase array is subdivided into over a 100 modules. This would seem to indicate that the radar may be capable of multi beaming.

Hmm. Interesting. That's quite different from this. 32 CFAs are combined into one transmitter.

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Page 4.

THE SPY-1D The SPY-1D was deployed on the first 40 destroyers (DDG-51 to DDG-90).10 It is similar to the 1B(V) version, except for using one transmitter for all four radar faces instead of two transmitters each powering two faces as in the cruisers.

Page 5

THE SPY-1D(V) The SPY-1D(V) is a “littoral warfare” (near-shore) version of the radar deployed on the subsequent Aegis destroyers (22 so far), starting with DDG-91 in 2005. This upgrade added a number of waveforms for improved clutter rejection and moving target detection to improve the capability of the Aegis radar in environments with ground and other near surface clutter. It also increased the transmitter average power (by at least 33 percent) and added a dual-beam capability which enabled it to put out two beams simultaneously (out of opposite faces).11 None of the 1D(V) ships has yet received a BMD upgrade.

Page 6

EMITTED POWER As noted above, the 1B and 1D versions are nearly identical except that the 1B version uses two transmitters each powering two antenna faces, whereas the 1D version has one transmitter for all four faces.

The SPY-1A’s transmitter output is provided by 32 crossed field amplifiers (CFAs), each with peak power of 132 kW, which would give a combined peak power of 4.2 MW.

 

[Anlsvrthng]

Yes, but can you still explain exactly how that can be done? A single PESA transmitter does not multitask. If its an AESA its possible because you can have a small set of elements doing something completely different from the rest, and because each has its own independent transmitter, it can be used to create its own waveforms for communication while the rest do the radar job.

A monostatic radar on its own doing multitask , using the same antenna as transmitter and receiver.
Compared to this to use the antenna as a super high speed directional data transmitter and receiver is a trivial task..


The above mans that if the radar operator cut into half the aperture to use parts of it for communication, 4k movie download and so on then range of radar will decrease by square(2), the scanned surface to half, the scanned volume to quarter.

The aperture loss is more sever than the power loss.

So even if spiting the aperture trivial on the AESA, no sane operator will sacrifice the range of the radar .

And from communication standpoint, the whole aperture can communicate several magnitude faster and with way higher jam resistance than a small portion of it.