Shipbucket

A new round of Project 956 upgrades and I think we'll be mostly done here.

Let's look now at mid-life upgrades geared towards air defense.
The first case study below is the Moskovskiy Komsomolets, since then known IRL as the Nastoychivy. One of the last of the series, it is shown below in a late-90s semi-experimental configuration with a first-generation phased array radar complex built atop the bridge. The same radar housing has been explored earlier on the Projekt 956.2.
To make space for the radar array, the pyramidal foremast and the Fregat radar have been removed, and a small lattice mast added to house the navigation radars and various comms systems.
In addition, the standard Pr.956U mainmast has been built atop the stack to house a backup Pozitiv radar.


The phased array shown above being late-90s state of the art, it is a fairly simple passive-freqscan array in short wavelength, designed primarily for medium-range target acquisition. Barring a longer wavelength, more power and/or smarter scanning modes, that first configuration lacks in long-range air detection capabilities. Compare for example with the Pr.956.2 configuration, where the scanned array is backed up by a C-band Podberyozovik radar.
To correct this, a longer-ranged radar would be rebuilt atop the PAR housing. The space available prevents installing a Podberyozovik in either version, so a legacy Fregat is re-installed instead.
The rear mast still carries some version of Pozitiv (probably freqscan) to handle target acquisition for the newly installed Kortik CIWS.
To take full advantage of the completed radar outfit, the Uragan arm launchers are replaced with two pairs of 12-cell 3S90M VLS bins, for a total of 48 9M317M SAMs. As mentioned earlier, this reduced loadout requires less structural modification than the 72-cell installation on the Pr.956.2.


Years later, a fully multi-mode scanned array is built at last on the Moskosvskiy Komsomolets, in place of the earlier array. Under the lengthened rectangular covers hide three arrays per quadrant: a main square array of some 2m on the side, working between bands C and X on medium-range 3D scan and target acquisition; a horizontal L-band array, covering longer ranges and LO contacts, but lacking in resolution (particularly in altitude); and a small IFF interrogator working in higher X/Ku band.
To reduce redundancies and topweight, the mainmast Pozitiv is removed entirely. Most of the fire director radars are removed, only 3 new-generation directional AESAs being retained for better integration with the gun systems and to ensure backup against saturation attacks.
At last, the Moskit launchers are dismounted and replaced by an UKSK VLS on the stern and a second pair of Kortik CIWS. A new Oniks-related ESM/datalink suite is installed to replace the Band Stand surface-search radar.



Now for something slightly different. Bystriy below is shown in a mission-specific configuration following a possible late-2000s/early-2010s refit.
- A second-generation phased-array radar is installed, this time without backup radar.
- Uragan launchers have been replaced by multi-mission VLS packs based on the Uragan's missile envelope.
- The Moskit bins are long gone, and a VLS array has been installed astern
- The stern VLS block, however, isn't the usual UKSK fit, but has been cut down to accommodate the same shorter multi-mission VLS replacing the Uragan launchers.
- In place of the Moskits, and instead of the usual second CIWS pair, a pair of trainable rocket launchers have been fitted for field trials. These are twice-removed descendants of the unrealized Trezubets close-in SAM system of the 90s. This version carries a much larger amount of tubes for various projectiles (high-velocity SAMs, chaff/flare rockets, ASW/anti-torpedo rockets, explosive rockets...) as well as a built-in EO fire control with laser-beamrider missile control channel
- The overall EO outfit of the ship has been significantly buffed up, with multiple instances of the Kashtan-3M already mentioned, here in a multirole version including a laser designator, as well as a new EOFC with multi-target capability and optics-jamming power
- The mainmast has been rebuilt around an ESM/datalink array developed for the Kalibr system and used here to control short-range cruise missiles, as well as a new circular 2D AESA combination surface-search radar, IFF and ship-to-ship datalink (based on erik_t's suggestions and Ametist's Krab navigation radar) replacing the legacy Palm Frond installation.
One internet cookie and all my admiration to the first to guess the mission this version is designed for!

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I'll attempt deeper thoughts tomorrow (these are very nice drawings, to be sure): were USSR/CIS IFF interrogators really X/K band?

I have no concrete info, but 'Jane's Radar and Electronic Warfare Systems 1990-91' says of Square Head, "Recent information strongly suggests that the system operates in G-band."
Generally the entry on Soviet IFF systems is just a list, nothing then was really known about the specs of Soviet IFF systems (at least in the public domain).

Great drawings as ever. I really like the Trezubets descendent multi-purpose rocket/missile launcher system, I think that would have appealed to the Soviet designers. I also feel there still would be some kind of gun-CIWS too, I assume the CIWS aft is a gun/missile mount?

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Good point, I blithely ran into a wall with this one, with the matter-of-fact exhilaration that comes from a complete disregard that facts may even exist.
My initial assumption was completely devoid of any thought about an established common band, and veered towards finer discrimination rather than range, hence the high frequency. The idea was that that short-wave sub-array could also handle short-range target handover.

I can find little enough about Soviet IFF frequency, so far:
- The legacy Nikhrom/Kremniy Soviet IFF system from the 60s was considered compromised and started being replaced with the Parol system in the 80s. Target date for the switch-over was 1995, but it was apparently never finished.
- I still consider Parol the baseline for these designs, if possible with a backup civilian mode on US IFF band.
- Current US/NATO IFF systems work slightly above 1GHz
- The only input I can find for Parol so far gives it two bands at 740MHz and 750MHz, which if confirmed puts its well into the other end of the spectrum from my assumption, into UHF territory.

Since the integrated array I described also included an L-band plate for long-range and LO work, does it sound more likely that it would be the one handling IFF, with a main frequency shifted into C-band?
And it turns out that Salyut is marketing a G-band naval IFF array...
OTOH the Square Head might be the interrogator for the Nikhrom system (can't confirm it clearly but it mostly matches from ship to ship), which I have seen associated with the legacy Soviet Kremniy system mentioned above. But then that would mean that Salyut (and by extension Agat) is pushing an IFF module inside a top-notch integrated mast, using a frequency band for an IFF system that has been blown open more than 30 years ago? If so, that probably means that Parol is a wash, or not successful enough for export clients to be interested in it.
In any case, G-band falls within the working range of my main air-search plate, so if we're considering a full-fledged AESA with real-time signal coding, I guess it could handle the IFF itself?
These thingies (still have to find a name for them) lose a lot from the side view IMO, with the mount and guidance unit 90% hidden by the rocket pods. Still, such a multi-function system needs a large loadout in addition to an insanely fast reload cycle and some kind of hand-picking area upstream from the on-mount magazine to adapt the loadouts to the threats.
The Trezubets is fairly obscure, I can't get anything on it beyond a name (coincidentally associated with the Ukrainian trident which obviously hogs the Google hits), a sparse line drawing, a caliber (220mm) and a presumptive range (1,5km). With these stats (wonky as they are) and the bulky look of the design, I don't see it entering service whatever happens. But Erik's explanation about the multi-role NLOS pallets on his fusion DDG and the EAPS C-RAM made me reconsider a concept I had for a trainable soft/hard-kill launcher to replace the PK-2, and decide it would be woefully underpowered for a safe hard-kill. Then one thing led to another, mission creep set in, and now I still have to define the calibers and tube lengths I need for each mission and platform. It's starting to feel too multi-role and elegant for a Soviet design...
And yes, the CIWS between helipad and hangar is my home-brewed version of the Pantsir-K (compacted and stealthified a bit from what has been seen IRL so far), which still carries the twin 30mm Gatlings from the Kortik. The smaller Meta-Trezubets further astern in place of the RBU-1000 is the smaller self-defense-only version geared towards anti-missile and anti-torpedo work.

Edit: I have updated the drawing of the Bystriy above to show the projectiles of the two Trezubets-2 launcher types.
Re-edited for sloppy typing.

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