5 ms·

Anomalous propagation and the sinking of the Russian warship Moskva

145 points by mkoster 3y ago

jihadjihad 3y ago
That's wild. So was it some temperature inversion near the surface of the water or something, where the air was cooler below than above?
- 1letterunixname 3y ago
  It explains it in the paper on pages 6-8.
Tommstein 3y ago
Makes me wonder whether the more competent militaries of the world take this kind of stuff into account when considering whether they're safely out of enemy radar range.
- fbdab103 3y ago
  "They couldn't hit an elephant at this distance." Probably best practice to always assume enemy range is significantly better than reported.
RA2lover 3y ago
Wasn't the Moskva spotted by a drone before missile deployment? 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.
- shbooms 3y ago
  > Wasn't the Moskva spotted by a drone before missile deployment? 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.
weatherlight 3y ago
I feel like this is a known tactic. the US Army has been using scatter communications since the Vietnam War to make radio communications go further.
- bell-cot 3y ago
  IIR, this atmospheric effect on radar ranges was first noticed (and taken advantage of) during WWII.
aaron695 3y ago
[dead]
photochemsyn 3y ago
[flagged]
- 0xDEADFED5 3y ago
  this is a narrow topic involving interesting science, not a polarizing political debate. there are plenty of other places on the internet to argue about politics.
  - photochemsyn 3y ago
    I've noticed a rather curious silence on the issue and I'm sure many others have as well. Here's some interesting narrow technological content on the issue, let's see what happens: https://www.forbes.com/sites/erictegler/2023/11/03/a-new-micro-kind-of-electronic-warfare-may-be-unfolding-in-gaza/ https://www.forbes.com/sites/erictegler/2023/11/03/a-new-mic...
    - whatshisface 3y ago
      Topics are pushed off HN by people losing their cool in numbers too large for the usual "three dead comments at the bottom" process to work.
1letterunixname 3y ago
Interesting. 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-us-air-force-f-117-was-shot-down-heres-how-it-went-down-37762 https://nationalinterest.org/blog/buzz/stealth-shootout-1999...
fancazzista 3y ago
Or it was simply located by one of the many, many NATO spy planes circling around in the Romanian territorial waters.
- avs733 3y ago
  Located and targeted are different. Until Ukraine recently got patriot batteries and humans I highly doubt anything they have could be cued by the NATO radars. More importantly I doubt the us would, and I’m not even sure most strategic isr resources like you think of could pass targeting data in real time to missle systems.
  - hef19898 3y ago
    There is not much about the Neptune online, the system tested in aprallel so (Wikipedia is great dor stuff like that) has automtic and manual guidance systems. Ukraine choose Neptune over that other system, so I assume Neptune has the same. 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.
  - hurryer 3y ago
    Ships move slowly, you don't need integration, you can input by hand the coordinates. The missile has terminal stage radar guidance. Ukraine also had a Bayraktar drone flying around the ship area at that time. It could have picked up rough coordinates from that.
  - sgt101 3y ago
    Even in the 1990's missiles would re-acquire targets after losing them - or after turning off their active targeting systems in order to prevent countermeasures being taken against them. 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.
gridspy 3y ago
https://web.archive.org/web/20231117010516/https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-23-0113.1/BAMS-D-23-0113.1.xml https://web.archive.org/web/20231117010516/https://journals.... 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.
- Already__Taken 3y ago
  Can anyone that makes radar comment: does this just work or does that kit need to understand that this can happen to process it. Is an operator just using the thing and for a couple house is surprised at how much more shows up? 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."
  - bell-cot 3y ago
    Not an expert, but - the echo-return delay (speed of light, out & back, for a more-distant target) will be longer than normal during such anomalies. Useful military radar needs all sorts of "filters" - to ignore spurious signals & stuff you don't care about & enemy jamming & the old microwave in the break room. So, bare minimum, the radar's filters would need to be designed with an awareness that (at times) it could spot real surface targets at much longer ranges than normally possible.
  - simne 3y ago
zmgsabst 3y ago
Or like carrots being good for eyesight, this is a convenient cover for other assets used. 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 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.
- fbdab103 3y ago
  Agreed. There are so many potential observers who could have detected the craft, feels far more likely that there was someone who had a good bead on the target.
- throwaway290 3y ago
  If you are told "there's a sniper in that window" it's critical info but you still need to aim your gun precisely with your eyes since "that window" is big enough that you can shoot all your ammo before you hit. Radar is the eyes of anti-ship missiles
anovikov 3y ago
It is well known and even footage of the actual battle has been released, that Moskva was detected using Bayraktar TB-2 drone. Which also acted as a decoy to make the ship pointing it's air defence system (which has 180 degree coverage) in it's direction to counteract any attempt of attack from it (the drone was beyond engagement range). Thus letting Ukrainians attack with missiles from the other direction, leaving ship with only short-range air defences to protect itself, that didn't do the job.
- hkpack 3y ago
  It is interesting that any rumor can become “well known” after person with big following talks about it. 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.
  - marshray 3y ago
    > having Byraktar nearby would have raised alertness of the crew 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.
    - hkpack 3y ago
      Yeah, this theory was in the same "package". 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.
fattless 3y ago
Man everything was against this ship. 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.

145 points by mkoster 3y ago

That's wild. So was it some temperature inversion near the surface of the water or something, where the air was cooler below than above?

1letterunixname 3y ago
It explains it in the paper on pages 6-8.

Tommstein 3y ago

Makes me wonder whether the more competent militaries of the world take this kind of stuff into account when considering whether they're safely out of enemy radar range.

fbdab103 3y ago
"They couldn't hit an elephant at this distance." Probably best practice to always assume enemy range is significantly better than reported.

RA2lover 3y ago

Wasn't the Moskva spotted by a drone before missile deployment? 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.

shbooms 3y ago
> Wasn't the Moskva spotted by a drone before missile deployment? 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.

weatherlight 3y ago

I feel like this is a known tactic. the US Army has been using scatter communications since the Vietnam War to make radio communications go further.

bell-cot 3y ago
IIR, this atmospheric effect on radar ranges was first noticed (and taken advantage of) during WWII.

aaron695 3y ago

[dead]

photochemsyn 3y ago

[flagged]

0xDEADFED5 3y ago
this is a narrow topic involving interesting science, not a polarizing political debate. there are plenty of other places on the internet to argue about politics.
- photochemsyn 3y ago
  I've noticed a rather curious silence on the issue and I'm sure many others have as well. Here's some interesting narrow technological content on the issue, let's see what happens: https://www.forbes.com/sites/erictegler/2023/11/03/a-new-micro-kind-of-electronic-warfare-may-be-unfolding-in-gaza/ https://www.forbes.com/sites/erictegler/2023/11/03/a-new-mic...
  - whatshisface 3y ago
    Topics are pushed off HN by people losing their cool in numbers too large for the usual "three dead comments at the bottom" process to work.

1letterunixname 3y ago

Interesting. 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-us-air-force-f-117-was-shot-down-heres-how-it-went-down-37762 https://nationalinterest.org/blog/buzz/stealth-shootout-1999...

fancazzista 3y ago

Or it was simply located by one of the many, many NATO spy planes circling around in the Romanian territorial waters.

avs733 3y ago
Located and targeted are different. Until Ukraine recently got patriot batteries and humans I highly doubt anything they have could be cued by the NATO radars. More importantly I doubt the us would, and I’m not even sure most strategic isr resources like you think of could pass targeting data in real time to missle systems.
- hef19898 3y ago
  There is not much about the Neptune online, the system tested in aprallel so (Wikipedia is great dor stuff like that) has automtic and manual guidance systems. Ukraine choose Neptune over that other system, so I assume Neptune has the same. 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.
- hurryer 3y ago
  Ships move slowly, you don't need integration, you can input by hand the coordinates. The missile has terminal stage radar guidance. Ukraine also had a Bayraktar drone flying around the ship area at that time. It could have picked up rough coordinates from that.
- sgt101 3y ago
  Even in the 1990's missiles would re-acquire targets after losing them - or after turning off their active targeting systems in order to prevent countermeasures being taken against them. 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.

gridspy 3y ago

https://web.archive.org/web/20231117010516/https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-23-0113.1/BAMS-D-23-0113.1.xml https://web.archive.org/web/20231117010516/https://journals.... 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.

Already__Taken 3y ago
Can anyone that makes radar comment: does this just work or does that kit need to understand that this can happen to process it. Is an operator just using the thing and for a couple house is surprised at how much more shows up? 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."
- bell-cot 3y ago
  Not an expert, but - the echo-return delay (speed of light, out & back, for a more-distant target) will be longer than normal during such anomalies. Useful military radar needs all sorts of "filters" - to ignore spurious signals & stuff you don't care about & enemy jamming & the old microwave in the break room. So, bare minimum, the radar's filters would need to be designed with an awareness that (at times) it could spot real surface targets at much longer ranges than normally possible.
- simne 3y ago

zmgsabst 3y ago

Or like carrots being good for eyesight, this is a convenient cover for other assets used. 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 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.

fbdab103 3y ago
Agreed. There are so many potential observers who could have detected the craft, feels far more likely that there was someone who had a good bead on the target.
throwaway290 3y ago
If you are told "there's a sniper in that window" it's critical info but you still need to aim your gun precisely with your eyes since "that window" is big enough that you can shoot all your ammo before you hit. Radar is the eyes of anti-ship missiles

anovikov 3y ago

It is well known and even footage of the actual battle has been released, that Moskva was detected using Bayraktar TB-2 drone. Which also acted as a decoy to make the ship pointing it's air defence system (which has 180 degree coverage) in it's direction to counteract any attempt of attack from it (the drone was beyond engagement range). Thus letting Ukrainians attack with missiles from the other direction, leaving ship with only short-range air defences to protect itself, that didn't do the job.

hkpack 3y ago
It is interesting that any rumor can become “well known” after person with big following talks about it. 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.
- marshray 3y ago
  > having Byraktar nearby would have raised alertness of the crew 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.
  - hkpack 3y ago
    Yeah, this theory was in the same "package". 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.

fattless 3y ago

Man everything was against this ship. 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.