investigating SA-5 still tracking after broken lock.

[diditopgun]

Hi !

It happened first time in MP then I was able to reproduce in SP (track attached).

SA-5 fired, RWR's missile launch alarm.

I did a defensive maneuvre and broke the lock. RWR alarm stop.

I regained altitude, still 5 on RWR but no alarm sound.

SA-5 missile still guided and shot me down.

SA-5_RWR_Bug.trk

[Tasmanian]

SA-5 doesn't change emissions upon launch. There should be no RWR warning in the first place.

[Flappie]

On 11/25/2023 at 7:04 PM, Tasmanian said:

SA-5 doesn't change emissions upon launch. There should be no RWR warning in the first place.

Do you have a source?

[Tasmanian]

Hi,

Please see the attached documents.

I couldn't find any mention of emissions change upon launch. Phase modulation is used explicitly to determine the target range. Missles can (in some scenarios must) be launched even in monochromatic emission mode. 

 

The only extra emissions may come from the missile transponder, but it should be directional (why not), and shouldn't trigger RWR.

 

Regards,

Yury

общие сведения о с-200.djvu зрк с-200.djvu стрельба зур 200.djvu лекции по рпц с200.djvu правила стрельбы с-200.djvu

[Whiskey11]

On 12/10/2023 at 11:46 AM, Tasmanian said:

The only extra emissions may come from the missile transponder, but it should be directional (why not), and shouldn't trigger RWR.

Regards,

Yury

The missile uplink channel could be detectable by western RWR and be the trigger for a launch warning. 

 

The S-200's 5N26 Square Pair track radar is a CW illumination antenna with a separate missile downlink/uplink antenna. The only purpose the uplink has is to arm the warhead or self destruct the missile. It's not a guidance channel so in a lot of ways you can think of the Square Pair like an aircraft radar launching any SARH missile, except launching an S-200 missile doesn't necessarily require them to ever arm the warhead. The downlink channel is for weapon health while sitting on the launcher.

 

There is, however, one major change in radar state right before a launch. It depends on the range but the two modes of operation for a Square Pair radar has one mode with range known, and the other with a range unknown.  The first indication is the range unknown mode. If a missile is launched in that mode, it's launched entirely in P-nav guidance and it has no "loft" or other trajectory. It is going to go directly to the SARH return. 

 

The second mode is usually utilized, especially at range, because it provides the best ballistic profile for the missile.  In this mode the radar switches to a modulated frequency to gain range information. This can take UP TO 30 seconds because the ranging is done manually by the operators. 

It's entirely possible that Western RWR differentiate the two modes and assume the change from range unknown to range known is an indication for launch. That would be VERY simplistic, but it's more likely they are picking up the missile uplink signals for the launch and using that. 

 

I don't speak Russian, but I'll check out the sources you posted and see if I can't find a way to translate them since the S-200 is my favorite Soviet SAM system and it interests me greatly! 

[NineLine]

I have asked the team to review this thread. Thanks. 

[Tasmanian]

 

Hi,

I would like to share some of my findings.

On 12/15/2023 at 1:20 AM, Whiskey11 said:

...a separate missile downlink/uplink antenna.

According to the documentation, the antenna is receive-only.

It is not used to arm the warhead. The warhead is armed by the missile program in two stages. The first one is timer-based. The second one is triggered by the angular velocity of the missile's line of sight.

I couldn't find any description or procedure to terminate the missile. At this point, it seems like sending a self-destruct command is not possible. If you find something, please let me know, I'm also very curious.

I only found that self-termination is triggered when the on-board power source is depleted.

On 12/15/2023 at 1:20 AM, Whiskey11 said:

There is, however, one major change in radar state right before a launch. It depends on the range but the two modes of operation for a Square Pair radar has one mode with range known, and the other with a range unknown.  The first indication is the range unknown mode. If a missile is launched in that mode, it's launched entirely in P-nav guidance and it has no "loft" or other trajectory. It is going to go directly to the SARH return. 

 

The second mode is usually utilized, especially at range, because it provides the best ballistic profile for the missile.  In this mode the radar switches to a modulated frequency to gain range information. This can take UP TO 30 seconds because the ranging is done manually by the operators. 

It's entirely possible that Western RWR differentiate the two modes and assume the change from range unknown to range known is an indication for launch. That would be VERY simplistic, but it's more likely they are picking up the missile uplink signals for the launch and using that. 

This is partially true. There are two main operating modes, and only one can provide the range. The RWR can likely differentiate the two modes but neither of them indicates a launch.

Below is the table that shows the recommended modes for a single target.

Targets above 1km altitude are engaged in the monochromatic mode, the one that doesn't provide the range. Lock-after-launch is possible only in this mode.

The Phase-modulated mode is typically used for low-flying targets or targets within a group.

There is a whole section on which mode to use depending on the conditions, and I can't post it here.

The range can be entered manually using other data sources or briefly using the phase-modulated mode.

If the range is unknown, two missiles can be launched in different modes, one in P-nav, and another in a long-range mode with loft, etc. This is achieved by manually entering different ranges before each launch.

 

The B-880 missile transponder doesn't emit unless the missile loses lock. It is mentioned that this is specifically done to conceal the launch.

B-860 missiles do emit but I don't know which RWR can detect it and at what range.

The document mentions that the pattern is within ±45 degrees along the missile axis. However, it doesn't mention whether it is true for the frontal hemisphere.

 

I attached another S-200 manual. I hope it helps.

 

Regards,

Yury

учебник по с200.djvu

 

Edited December 17, 2023 by Tasmanian

[NineLine]

On 11/24/2023 at 2:58 PM, diditopgun said:

Hi !

It happened first time in MP then I was able to reproduce in SP (track attached).

SA-5 fired, RWR's missile launch alarm.

I did a defensive maneuvre and broke the lock. RWR alarm stop.

I regained altitude, still 5 on RWR but no alarm sound.

SA-5 missile still guided and shot me down.

SA-5_RWR_Bug.trk 1.31 MB · 1 download

Hi, I created a test with the F/A-18C and when I popped back up I did again get the lock and missile warning as the missile continued to guide on me. So I think, unless I misunderstand your issue, that this is an issue with the F-14 and you will need to report it to Heatblur. Thanks!