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#3597997 - 06/27/12 07:55 AM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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A question to Hpasp (or piston79 wave):
Does a 5V28 missile's GSN do doppler processing of the received signal (look for speed) or is it simply looking for the strongest received signal at given base frequency with some band around it?
I suppose it does a processing - GSN mode DO STARTA can be set to POISK V VKL so I think in this mode Plamja before launch uploads target speed and other data like flight profile to a flight computer and missile in a moment of launch looks for the given doppler velocity. In contrary when POISK V is VYKL (home on jam) missile does not look for target's speed. Am i correct?

I was thinking about the Tu accident and it led me to this idea. Does also the flight computer do some processing (or maybe not processing, there were no digital signal processors at that time) of the recived signal or does it at least monitor for example doppler frequency of received signal? Or the entire processing is done by GSN which then sends results to the computer which controls missile's steering wheels?
In other words if such a "target swap" can be possible - dramatic change of doppler velocity should be ignored by missile (but we do not know if both doppler speed weren't close to each other).
And I think that accident was strange either - the Tu plane was more than 200km far and despite it's large RCS I doubt it would create significantly stronger RSSI than the test target, which was indeed much closer (and experience with SAMSIM what RSSI vs different targets does makes me more sure). I think (if it was shot down by Vega) it was shot down intentionally (probably by a SAM crew's fault).

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#3598037 - 06/27/12 10:36 AM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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GSN 5G24 on 5V28 missile could search automaticcaly for target in case of lost autotracking. It searches the dopller signal (speed determination of the targets).

#3598040 - 06/27/12 11:01 AM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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Yes, beacause of POISK V is VKL (search for velocity enabled), so I was correct. But what is the algorithm for it? How does it work when another target with different RSSI and probably different doppler speed is in the field of view of GSN (Ukrainian accident)?

Do you know how many missiles was shot against a test target? If there is a significat delay between launches and the target splashed away (so the 5N62 lost tracking) missile would continue on its path searching for the target. But it does so only for a limited time, after its expiration missile should autodestruct. But what is the probability that the plane accidentaly shot down would stay in the static (not moving) beam of 5N62 so the missile would acquire it and stay in it for such a long time before missile reaches it and explodes?
What was distance of a test target and the plane?

In case the 5N62 would not lost tracking (would keep lock on some falling remnant of a test target), then the second missile would be guided into it.

The more I think about that accident the more I know that I know nothing nope and it seems more and more suspicious to me.

Again it leads me to a hypothesis that the plane was acquired, tracked and shot down (if it was really hit by that Vega battery).

Last edited by Alien_MasterMynd; 06/27/12 11:08 AM.
#3598043 - 06/27/12 11:12 AM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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#3598050 - 06/27/12 11:45 AM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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And do you know how far it was?

#3598056 - 06/27/12 12:01 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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I did a quick calculation - 5N62 beam 1.4 degrees wide, target distance 200km. So the beam diameter at that distance is 4.88km. If the target would go at beam crossing speed of for example 200m/s . So the beam would be crossed in about 30s (effective beamwidth would be greater than mentioned 4,88km since the target is crossing it with angle different from 90 degrees to a radar boresight). Let's assume missile is flying at 1200m/s (may be slower for the given distance), so it results in test-target - Tu-154 distance of about 36km!!!! And no one will place test target such close to an air traffic corridor. So again I think the Tu-154 had to be tracked by 5N62. And again just in case it was really a Vega hit.

Last edited by Alien_MasterMynd; 06/27/12 12:14 PM.
#3598091 - 06/27/12 01:17 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Alien_MasterMynd]  
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Originally Posted By: Alien_MasterMynd
I did a quick calculation - 5N62 beam 1.4 degrees wide...


nope
1.4 degree wide only during target acquisition.
During target tracking it narrows down to 0.7 degree automatically.
(check "C" panel, or manual page 14)
cowboy

Last edited by Hpasp; 06/27/12 01:18 PM.

Hpasp
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#3598107 - 06/27/12 01:48 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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Yes, I assumed tracking lost, so back to acquisition. Just the worst case to have crossing time as long as possible. To get the theory about misledaded missile biggest chance :-)

While tracking the other target the situation would be much worse because both targets should follow the same trajectory (as projected to radar and missile).

PS: while in SIR mode, the received signal of course would be weaker because the same energy is spread to the larger beam, but missile is already on its way and is significantly closer to the target.

Last edited by Alien_MasterMynd; 06/27/12 01:53 PM.
#3598186 - 06/27/12 04:06 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Alien_MasterMynd]  
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Originally Posted By: Alien_MasterMynd
A question to Hpasp (or piston79 wave):
Does a 5V28 missile's GSN do doppler processing of the received signal (look for speed) or is it simply looking for the strongest received signal at given base frequency with some band around it?


GSN is tracking the target in...
- Elevation and Azimuth coordinates compared to the missile axis. (Always)
- Doppler missile-target closing speed between 100-3500m/s. (except if you aim a jamming target)
- Range (in case of FKM signal emitted by the RPC)


Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

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#3598201 - 06/27/12 04:18 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Alien_MasterMynd]  
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Originally Posted By: Alien_MasterMynd
Yes, I assumed tracking lost, so back to acquisition. Just the worst case to have crossing time as long as possible. To get the theory about misledaded missile biggest chance :-)


I would rather bet on misidentified target.

SAM simulator is not emulating IFF systems, and their possible problems...
... I can easily imagine a situation, where the RPC locks on the passenger plane 70km away from the target drone, and receives positive IFF check.
(If the target drone had an on-board IFF, saying "I'm your target".)

grunt

PS: Also do not forget, that the 5V28M V-880M (SA-5C) missile has 300km range.

Last edited by Hpasp; 06/27/12 04:41 PM.

Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

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#3598229 - 06/27/12 05:03 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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Originally Posted By: Hpasp

PS: Also do not forget, that the 5V28M V-880M (SA-5C) missile has 300km range.


But the actual distance to the target in this case was around 350 km. I experimented with SAM Sim and Boeing 747 over Hungary, and I must admit that in MHI mode the received signal strength at that distance just reaches the required 25 dB, so it was theoretically possible for the homing head to lock on such aircraft. It looks like the missile far exceeded its performance limits, especially if it was S-200V, not S-200D. At the other circumstances this might be something its designers could be proud of... nope

#3598236 - 06/27/12 05:13 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Lonewolf357]  
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Originally Posted By: Lonewolf357

But the actual distance to the target in this case was around 350 km.


As nobody knows the place of the wreckage, we cannot measure its distance from any S-200 Site.
Also be aware, that the Dunbna's RPC has increased power output, compared to the Vega. (approx +10dB)

Last edited by Hpasp; 06/27/12 05:16 PM.

Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

thumbsup
#3598243 - 06/27/12 05:27 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Alien_MasterMynd]  
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Quote:
Yes, beacause of POISK V is VKL (search for velocity enabled), so I was correct. But what is the algorithm for it? How does it work when another target with different RSSI and probably different doppler speed is in the field of view of GSN (Ukrainian accident)?


What I've read in a forum was that the target and the passanger plane was in the beam at the same time, and the target drone just "slips away".
Here you can see how the GSN works when searching for doppler signal return:
Click to reveal..

Shortly, it scans in a 2 ways (wide and narrow) and always goes from higher velocities (i.e. higher radial speed).
BDP is "Bolshoy diapazon poiska" - wide search diapazon
MDP is "Maloy diapazon poiska" - narrow search diapazon
SC is "Signal Cel/Tzel" - target return
SS is "Signal Svoego samoleta" - Own target return
NP is "Naprawlenie poiska" - vector of search on speed..

Here, danger zone for own ragets:


Here, distance to target and distance between target and own target safety zone:


My humble opinion is the target drone was more than 80 km away (thus allows high profile of the missile path), both targets were in the same radial speed (like Hawkeye and Tomcat), and due to strongest return of the Tu-154, RSN stays locked to him, nobody checks time of the missile flight and the worst happens.... frown

A link:
http://www.pravda.com.ua/rus/news/2001/10/9/4363197/

Last edited by piston79; 06/27/12 05:37 PM.
#3598244 - 06/27/12 05:30 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Lonewolf357]  
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Originally Posted By: Lonewolf357

But the actual distance to the target in this case was around 350 km. I experimented with SAM Sim and Boeing 747 over Hungary, and I must admit that in MHI mode the received signal strength at that distance just reaches the required 25 dB, so it was theoretically possible for the homing head to lock on such aircraft. It looks like the missile far exceeded its performance limits, especially if it was S-200V, not S-200D. At the other circumstances this might be something its designers could be proud of... nope


As some Dvina 80 km shots with disable self destruction mehanizm from NVA, and also Iraq converted Volkhov missile to SS type...

#3598264 - 06/27/12 06:06 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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Originally Posted By: Hpasp
Originally Posted By: Lonewolf357

But the actual distance to the target in this case was around 350 km.


As nobody knows the place of the wreckage, we cannot measure its distance from any S-200 Site.
Also be aware, that the Dunbna's RPC has increased power output, compared to the Vega. (approx +10dB)


I took the coordinates you have provided (4210'60.00"N and 3737'0.00"E) for the crash site, and found the S-200 positions in Google Earth (using Sean O'Connor's amazing SAM site overview from http://geimint.blogspot.com) at coordinates around N459.0' E035 44.0', which is a location of Ukrainian SAM firing range. Measuring the distance between these two points gives us whopping 362 kilometers. I wonder if this is a longest-range SAM shot ever?

And thanks for that little detail about S-200D, I always wondered if it has same power output as older versions or not. I wonder if more sophisticated missile trajectories were implemented as well, avoiding the overheating problem?

#3598272 - 06/27/12 06:19 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Lonewolf357]  
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Originally Posted By: Lonewolf357

I took the coordinates you have provided (4210'60.00"N and 3737'0.00"E) for the crash site, and found the S-200 positions in Google Earth (using Sean O'Connor's amazing SAM site overview from http://geimint.blogspot.com) at coordinates around N459.0' E035 44.0', which is a location of Ukrainian SAM firing range. Measuring the distance between these two points gives us whopping 362 kilometers. I wonder if this is a longest-range SAM shot ever?


Its around 300km for me, pretty long, but realistic shot.



Hpasp
Free SAM Simulator, "Realistic to the Switch"

(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/

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#3598274 - 06/27/12 06:20 PM Re: Tu-154M of "Syberia" - what really happens? [Re: piston79]  
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Originally Posted By: piston79
[quote]

My humble opinion is the target drone was more than 80 km away (thus allows high profile of the missile path), both targets were in the same radial speed (like Hawkeye and Tomcat), and due to strongest return of the Tu-154, RSN stays locked to him, nobody checks time of the missile flight and the worst happens.... frown

A link:
http://www.pravda.com.ua/rus/news/2001/10/9/4363197/


I think that this version...
http://forum-msk.org/material/power/6789.html
...also have a right to exist. It claims that initial lock on target drone was lost, and, due to deficit of time, they re-acquired the target and fired in MHI mode, without switching to FKM, so they didn't knew that they re-acquired the wrong target. Also, a possibility is stated that the other S-200 battery might have illuminated the Tu-154 during their target acquisition practice, and missile locked on it.

#3598283 - 06/27/12 06:29 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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Originally Posted By: Hpasp
Originally Posted By: Lonewolf357

I took the coordinates you have provided (4210'60.00"N and 3737'0.00"E) for the crash site, and found the S-200 positions in Google Earth (using Sean O'Connor's amazing SAM site overview from http://geimint.blogspot.com) at coordinates around N459.0' E035 44.0', which is a location of Ukrainian SAM firing range. Measuring the distance between these two points gives us whopping 362 kilometers. I wonder if this is a longest-range SAM shot ever?


Its around 300km for me, pretty long, but realistic shot.




Ah... I think you mis-placed the S-200 battery, it was located near Feodosiya at Ukraine, not near Novorossiysk in Russia wave
I think it is located here:


This is what my measurements give:

#3598313 - 06/27/12 07:18 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Hpasp]  
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[quote=Hpasp
I would rather bet on misidentified target.
[/quote]
That's what I wrote many times. Regarding Vega operation it is just impossible.

I gave misleaded theory great chance - just to see if it is impossible in this way, then everything not so optimistic is impossible too.

PS: they should verify the target many times, especially the had to see its range.

#3598318 - 06/27/12 07:26 PM Re: Tu-154M of "Syberia" - what really happens? [Re: Lonewolf357]  
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Quote:
I think that this version...
http://forum-msk.org/material/power/6789.html
...also have a right to exist. It claims that initial lock on target drone was lost, and, due to deficit of time, they re-acquired the target and fired in MHI mode, without switching to FKM, so they didn't knew that they re-acquired the wrong target. Also, a possibility is stated that the other S-200 battery might have illuminated the Tu-154 during their target acquisition practice, and missile locked on it


How could they, to have AS RPC they should use FKM first...? Also they claimed they put 50 km range... think that the missile couldn't reach 300 km with "Program I" flight....

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