SAM rework and modernization

[StealthySpace7]

BLUF, I would like to see SAM’s better modeled within DCS. I’ll be speaking primarily about the SA-2 but the points I bring up apply to other SAM’s in the game.

 

There are a few things on the in-game SA-2 that are modeled but not function such as the trough antennas on the Fan Song Target Engagement Radar (TER) that allow it to do its own limited search function. These antennas can scan a fixed area at a time or be combined with the rotation of the whole unit to provide 360 degrees of search.

 

Another thing missing on the Fan Song is its optical tracker. This allowed crews to track targets without the use of the 2 parabolic dish antennas mounted on top. Since the missile guidance was accomplished using Command Guidance instead of Beam Riding the target aircraft wouldn’t get a missile launch warning until the beam from the missile uplink antenna also encompassed the aircraft. This is also true for when crews tracked targets using the Radars, the aircraft would be alerted via its RWR (Radar Warning Receiver) that it was being locked onto, but the missile launch alert would not be given until the aircraft was in the same beam as the missile. 

 

For a brief explanation of why this happens continue reading this paragraph, if you already have a grasp of it feel free to skip to the next one. On radar's like the Fan Song that use command guidance, there will usually be antennas dedicated to tracking a target and antennas dedicated to missile guidance or, "talking to the missile." Because the radar's goal is to get the missile out in front of the aircraft to pull lead and not waste its limited energy, it will be fired with lead and the narrow beam of energy pointed at it to give it commands during flight will likely not encompass the aircraft until the missile and aircraft are very close (this scenario assumes a side aspect shot). The aircraft will be kept in the beam of a tracking antenna that works with a computer or the operator to tell the uplink how to guide the missile. 

 

The optical tracker is seen on most "E" models of the Fan Song radar which is the variant modeled in game, this is evident by the placement of the 3 parabolic dishes as well as the trough antenna's. 

 

From what I have read the SA-3's Low Blow radar includes similar trough antennas however it does not utilize them in the same search function, instead they act as receivers. 

 

These Trough antennas are fixed in place so they are limited in azimuth and elevation in terms of search capability, however the inclusion of these antennas mean systems like the SA-2 are not completely useless if the search radar is offline. 

 

Something to note is the choice of search radar for the SA-2 and SA-3 being the P-15 Flat Face in game. In real life as far as I've read the P-18 Spoon Rest was the intended Search Radar for at least later model SA-2’s such as the “D” model we have in game. It was also used with the SA-3, however the SA-3 also used a later version of the P-15 called the P-15M Squat Eye. Both the Spoon Rest and the Squat Eye include better performance over the Flat Face. 

 

Something that I cannot confirm (as I do not know how the guidance is modeled) but suspect to be inaccurate is the flight path taken by missiles using command guidance. Rather than being fired and leading the target they seem to lag behind it or travel directly to it as if they were beam riding. 

 

My final point on the SA-2 specifically is the maximum range of the system. The Target Tracking radar is the SNR-75M4 Fan Song E (it could also be the SNR-75M3 Fan Son E I have not been able to distinguish between the two systems based on our in-game model). The variant of SA-2 to use Fan Song E’s was the SA-2D which used the 5Ya23 missile. This missile has a maximum range of 76,000 m or 41.04 NM. The missile in game has a maximum range of 28 miles, which while being a more realistic firing range as it's much closer to the "no escape" range of the missile, is still short of the maximum range. It's important to note that the statistics for the type of missile used in game seem to be relatively accurate, I believe it is just the wrong missile being used for the variant of SA-2 we have. 

 

To conclude, I would like to see track radars have expanded functionality to match their real world counterparts, the variant of SAM specified (like SA-2B, SA-2C, SA-2D etc...) and the components and missiles of SAMs used in game synchronized and their specifications brought in line with the appropriate variant.

 

Thank you and Happy Holidays

 

Sources:

http://www.ausairpower.net/APA-Engagement-Fire-Control.html

http://www.ausairpower.net/APA-S-75-Volkhov.html

 

Both sources include other links to information

Edited April 7, 2023 by StealthySpace7

[upyr1]

2 hours ago, StealthySpace7 said:

Another thing missing on the Fan Song is its optical tracker. This allowed crews to track targets without the use of the 2 parabolic dish antennas mounted on top. Since the missile guidance was accomplished using Command Guidance instead of Beam Riding the target aircraft wouldn’t get a missile launch warning until the beam from the missile uplink antenna also encompassed the aircraft. This is also true for when crews tracked targets using the Radars, the aircraft would be alerted via its RWR (Radar Warning Receiver) that it was being locked onto, but the missile launch alert would not be given until the aircraft was in the same beam as the missile. 

 

I could be wrong but I think BAT 21 was shot down that way, 

[StealthySpace7]

21 hours ago, upyr1 said:

I could be wrong but I think BAT 21 was shot down that way, 

Yup. The first 2 or 4 shots (not sure it calls them volleys so I assume 2 shots per volley) missed with radar guidance, the next volley was done via optical guidance and scored a kill. 

[remus77]

This would be a nice addition. Agreed.

Edited December 27, 2022 by remus77

[Destroyer37]

Hopefully ED sees this thread and revamps all the systems not just the 2/3. Smarter SAM’s would be a really nice addition to the Sim. 
 

-Bucks.

[Furiz]

Nice work, hope to see this done by ED, would really make things more interesting.

[Kang]

More options in regard to how a given SAM site operates to better simulate its real counterparts would absolutely be good.

While I see that there is obviously a limit to what can be done given how many different systems are around and how we all like to have various options later on, I think it would also be a good opportunity to once again suggest something like a SAM module that would allow players to take proper simulated control of, say, a HAWK and a SA-6 for example. As multi-vehicle sites they are somewhat excluded from Combined Arms so far anyway and it might be a good way to get some payoff into further development of these systems.

[Northstar98]

On 12/26/2022 at 2:17 AM, StealthySpace7 said:

Since the missile guidance was accomplished using Command Guidance instead of Beam Riding the target aircraft wouldn’t get a missile launch warning until the beam from the missile uplink antenna also encompassed the aircraft. This is also true for when crews tracked targets using the Radars, the aircraft would be alerted via its RWR (Radar Warning Receiver) that it was being locked onto, but the missile launch alert would not be given until the aircraft was in the same beam as the missile. 

So far, looking at the link the uplink antenna seems to have a beamwidth of 15°, which is rather large. The other thing to consider is that RWRs may pick up sidelobes from the uplink antenna (whether or not they will depends on how sensitive they are and the radiation pattern of the antenna).

Suffice to say however DCS doesn't model this (though I wish it would) and in general AI radars are incredibly simplified - heck, there isn't much you could do to make them even more simplistic:

• They're immune to clutter
• They have very little of the beam modelled (the only thing really is beamwidth, but only for some radars and in those cases it's set to 90°)
• They don't differentiate between whether a radar is pulse, pulse-doppler/modulated CW or unmodulated CW, nor whether or not they're 2D or 3D capable
• None of their modes are modelled etc.

You'll also find a few examples where radars are just copied and pasted from each other, even for completely different radars (AN/SPY-1 and Mk 92 CAS are both copied and pasted from the AN/MPQ-53) and even when they aren't, there aren't many differences actually modelled. For instance the SNR-125 and SNR-75 are completely identical.

On 12/26/2022 at 2:17 AM, StealthySpace7 said:

Something to note is the choice of search radar for the SA-2 and SA-3 being the P-15 Flat Face in game. In real life as far as I've read the P-18 Spoon Rest was the intended Search Radar for at least later model SA-2’s such as the “D” model we have in game. It was also used with the SA-3, however the SA-3 also used a later version of the P-15 called the P-15M Squat Eye. Both the Spoon Rest and the Squat Eye include better performance over the Flat Face. 

We have the P-19 [Flat Face B] in DCS and AFAIK this is accurate to the S-125M 'Neva-M' [SA-3b Goa] system that we have. But as you correctly stated, the P-12 and P-18 are more appropriate radars for the SA-2. According to SAM simulator, the SNR-75 can be slaved in azimuth to the P-18 (with the operator of the P-18 selecting the azimuth).

This problem also applies to the S-200V 'Vega' [SA-5b Gammon], with even worse consequences. In DCS the radars assigned to it are the Flat Face and the Tin Shield, when neither are appropriate whatsoever for the SA-5 (the 5V28 missile outranges both radars by considerable margin and the P-19 is associated with the SA-3 and the Tin Shield with the SA-10 (though has seen use as a general-purpose EWR), given that we have the S-300PS [SA-10b Grumble] in DCS, the Tin Shield variant we should have is the 5N59S [Tin Shield B]). The actual radar associated with it is the 5N84A 'Oborona-14' (P-14F) [Tall King C]. I've spoken about this particular one here, here and here.

On 12/26/2022 at 2:17 AM, StealthySpace7 said:

Something that I cannot confirm (as I do not know how the guidance is modeled) but suspect to be inaccurate is the flight path taken by missiles using command guidance. Rather than being fired and leading the target they seem to lag behind it or travel directly to it as if they were beam riding. 

I can't say either way either, but suffice to say DCS doesn't have the respective modes available.

According to the documentation provided by SAM simulator, the SA-2d is supposed to have 3 primary firing modes (as well as a surface-attack mode):

• Half-Lead - in this mode the missile aims at a pre-calculated impact point (for high-altitude, high-speed targets)
• Three-point - in this mode the the target, the missile and the fire-control radar should represent 3 points on the same line, hence the name (for high-altitude, low-speed targets).
• K (which is half-lead, elevated by a constant) - in this mode the missile is guided as in half-lead but the aiming point of the missile is never positioned below the target (to be used at low altitudes, where a diving target could cause the missile to impact terrain).

The proximity fuse can also be set differently based on target parameters at low altitudes - with the target below 5000 m but at an elevation >1.5° the fuse should be set to the maximum of 300 m. If below 5000 m and an elevation <1.5°, the fuse should be set to 100 m.

On 12/26/2022 at 2:17 AM, StealthySpace7 said:

My final point on the SA-2 specifically is the maximum range of the system. The Target Tracking radar is the SNR-75M4 Fan Song E (it could also be the SNR-75M3 Fan Son E I have not been able to distinguish between the two systems based on our in-game model). The variant of SA-2 to use Fan Song E’s was the SA-2D which used the 5Ya23 missile. This missile has a maximum range of 76,000 m or 41.04 NM. The missile in game has a maximum range of 28 miles, which while being a more realistic firing range as it's much closer to the "no escape" range of the missile, is still short of the maximum range. It's important to note that the statistics for the type of missile used in game seem to be relatively accurate, I believe it is just the wrong missile being used for the variant of SA-2 we have. 

This is a bit of an interesting one as different sources say different things.

In DCS we supposedly have the V-755 (20D) missile, which seems correct for what Vestik PVO, the source ausairpower seems to cite, describes - in the description following ZRK S-75M "Volkov", the 20D missile is mentioned as an initial variant and the description of the radar matches that of the Fan Song E.

Free SAM simulator also has this setup with the 2 additional narrow-beam parabolic antennas and the V-755 missile (though gives the NATO designation and reporting name as SA-2e Guideline Mod 3).

As for the DoD/NATO designation, the cmano database states that this system is the SA-2d Guideline Mod 1. Unfortunately though wikipedia doesn't agree and Vestnik PVO doesn't say either way.

 

Otherwise, I completely agree and this is before we get into things like say, IADS.

Edited December 28, 2022 by Northstar98