Anomalous propagation and the sinking of the Russian warship Moskva
journals.ametsoc.org
journals.ametsoc.org
Abstract
On 13 April 2022, the Russian warship Moskva was hit by two Ukrainian Neptune anti-ship missiles in the Black Sea, leading to its demise. Before launching an anti-ship missile, a target must first be detected and positioned, for example by an accompanying radar system. However, when the missiles hit the Moskva she was well beyond the normal radar horizon of any ground-based radar system, making the ship undetectable under normal circumstances. Using meteorological reanalysis data, we show that at the time of the missile launch the prevailing weather conditions allowed a ground-based radar to detect targets far beyond the normal radar horizon through anomalous propagation conditions. During such conditions, the atmospheric index of refraction decreases rapidly with height, making electromagnetic radiation bend downward to, partly or fully, compensate the curvature of the Earth. The results show that atmospheric conditions must be considered carefully, even during warfare, as their impact on radar wave propagation can be considerable.
like a telescope operator would be like "huh that's new" where as my router will be like "hmm TCP just got bigger, stop working."
For example I used car FM radio to hear reflections from meteors, from Warsaw radio (about 1000km from me, usually, you may know, about 100km from transmission tower).
But modern digital usually just filter out all signals with too much delay.
Old analog radars (widely in use in Ukraine), really could see much farther when good conditions, and if engineers could tune circuit. And we have to tune, because need to make all possible, because of war.
Manual guidance wouod allow you to shoot the missile in the direction of the located target, until you are close enough for the missile to lock on and have it hit using automatic guidance. No idea what was done during hat particular attack, but it sure was possible without radar sorcery.
Ukraine also had a Bayraktar drone flying around the ship area at that time. It could have picked up rough coordinates from that.
It's plausible that Ukraine was told where the ship was, launched the missiles in that direction and they acquired and targeted the ship autonomously when they got closer. Of course that's pretty risky as a gambit but the downside was a failed strike and the upside was a doomed capital ship.
One could go so far as to say that "using Russian blood" has historically been and currently is their military doctrine.
Every way of spotting a target suffers from uncertainty. Most suffer from delays (satellite photo is X hours old), security issues (keep your spies alive), and political considerations (Ukrainians might want to feel that they are fighting and winning, not just acting as push-button-when-told minions of foreign powers).
Waiting to attack it until that could reliably be done with all-Ukrainian assets, all of which the Russians already knew about - that maximizes the number of checked boxes, eh?
- Ukraine performed the initial radar detection
- Ukraine asked the US to confirm it was the Moskva (the US did)
- Ukraine attacked with their own targeting data
Which sounds reasonable. Warships like the Moskva are strategic assets.
That lowers the bar for acceptable amount of help from the US before Russia escalates.
> Which sounds reasonable
If you don't know anything about radars, yes.
Eg, NATO observation craft or satellites.
Per Wiki, we have a satellite image from shortly after it was struck:
> An image from a satellite with cloud-penetrating synthetic aperture radar (SAR) revealed that at 18:52 local time (UTC+03:00) on 13 April 2022, Moskva was located at 45°10′43.39″N 30°55′30.54″E, about 80 nautical miles (150 km) south of Odesa, east of Snake Island and around 50 nmi (90 km) from the Ukrainian coast. An analysis suggested this was not long after the damage occurred which caused the ship to eventually sink. In the image, the cruiser is accompanied by other vessels.
And a US airplane in radar range when the attack happened:
> There was a US Navy P-8A Poseidon maritime surveillance aircraft in the area before the sinking. The P-8A from Italy was patrolling within its radar range over the Black Sea and the US, when asked, did identify the ship as the Moskva as part of intelligence sharing to help Ukraine defend against attack from Russian ships.
And a drone, likely operated by Ukraine:
> The operation to sink Moskva may have been assisted by the use of at least one Bayraktar TB2 drone (UCAV), which seems to have observed the event and may have played other roles in the ship's sinking. […]
> Mevlutoglu mentioned that Rear Admiral Oleksiy Neizhpapa, commander of the Ukrainian naval forces, had in the past suggested that TB2 drones would be used with Neptune launchers for target reconnaissance.
https://en.wikipedia.org/wiki/Sinking_of_the_Moskva
A boring but likely kill-chain:
1. SAR satellites spot the Moskva fleet.
2. US P-8 begins a track and feeds that data into shared intelligence.
3. US advisors alert Ukraine that Moskva is spotted and within engagement range.
4. Ukraine TB2 is flown on site, using that data.
5. Neptune launchers and missiles in flight are fed data from TB2.
In your analogy, you're firing a bullet in the right direction that can look and steer itself to the sniper.
This part is really hard to believe. I briefly worked with radar systems (though nothing classified) These systems are all ancient and janky don't just integrate like lego. You can't just take a radar feed from a drone and feed it into the control system of a cruise missile lol
Even AEGIS systems can't really do that effectively - let alone systems from two different countries (cutting edge military stuff is tech wise in like the 90s at best)
It's not impossible, and it's wartime.. So maybe some Ukrainian engineers hacked something together - but I find this part very unlikely
To me it seems much more likely they got a radar bounce back due to a freak weather phenomena
They may have been coming from the TB2, but they're being input by hand.
- Shore radar + TB2 work up track on Moskva (heading, speed)
- Missile launched to calculated intercept point
- If Neptunes have midcourse correction (?), point updated if Moskva changes courseI’m inclined to believe that a drone can relay targeting data as an admiral claimed over “freak radar returns” — as indirect fire is a standard event.
The missile performs its final homing under its own guidance anyways.
For whatever reasons it's own AA wasn't function properly so the chances to hit were exceptional.
I don't believe some folks on the shore would just scan the sea beyond the horizon just in case they could get a lock. That's not how it works. Maybe they could get a lock (it's still a possibility) but that's the difference between the targeting mode only.
It was a US intelligence operation from the start to the end.
People close to operation mentioned that having Byraktar nearby would have raised alertness of the crew, so it would not be beneficial. And the best luck was with a surprise attack. There was an interview with the commander of the unit and he mentions the atmospheric effect which allowed them to lock into the ship.
One theory I heard was that the drone was specifically used to distract the (mechanically steered) primary radar of the ship, thus allowing the antiship missiles to approach undetected from another direction.
People close to the matters told that this is most likely untrue and radars are capable of tracking from multiple directions.
Also, anaprop conditions are common and not something which happens ones in a hundred years.
Lock-on after launch is certainly a possibility, and one i see making more sense considering the 1/r^4 nature of radar echo reception and the fact there's not much point in dimensioning a radar system past its expected detection horizon under normal conditions.
Drones were speculated to have been involved but it was said they were used to distract the ship's defense system as the missiles were in the air, not in the initial spotting/targeting. Although I suppose they could've pretty easily done both.
Or tune your Soviet search radar down to the lowest setting to defeat stealth aircraft when their bomb bay doors are open just about when they're RTB.
https://nationalinterest.org/blog/buzz/stealth-shootout-1999...
Afaik, it was undergoing incredible mismanagement, a series of mechanical faults and poorly maintained systems. It meant that its air defense was down or severely limited, and their communications systems busted, they had to choose between communications with the crew or command. Once the ship was spotted, it couldnt defend against the missles and after the impact the crew could not communicate to address it.
All that from memory, im sure i got some details wrong but what a mess.
Probably best practice to always assume enemy range is significantly better than reported.