no bug SAMs don't detect bombs

[Aigle2]

DCS has a core issue. Take a SA-15. It can intercept HARMs fired at it. Good. But...not the bombs.

In multiplayer, everyone uses JSOWs and GBUs to kill SAMs, because they can't detect and fire at them in response. Which make them better than HARMs to do SEAD/DEAD. This is not realistic, because from the SAM's radar perspective, a missile or a bomb is the same kind of radar contact. And because bombs are slower, it should even be easier to intercept them.

I don't think their is any major technical issue to correct this. So...could you ED change that ? 

[BIGNEWY]

It very much depends on RCS values, if you have data that shows a particular weapon system can intercept a particular weapon system please share it with us in a PM if you need to. 

 

Without confirming data we are unlikely to make changes. 

 

thanks

[Tippis]

There are two slightly separate but related issues at play here.

 

One is that regular bombs simply don't have the “reflection” stat that sensors (including SAM search and tracking radars) use to identify and guide weapons onto target. Bombs aren't engaged by air defences because, from their point of view, they simply don't exist. The stat that would make them show up isn't there.

 

The other is that gliding weapons are internally defined as missiles, and those do get the reflection stat, but for whatever reason, gliding bombs are often given very tiny numbers.

 

The JSOW has a reflection of 0.05 to 0.0618, depending on variant (this is meant to be an abstraction of effective nose-aspect RCS in m², more or less).

The LS-6 has a reflection of 0.07.

The GB-6  has a reflection 0.1.

The BK-90 has a reflection of 0.4.

The AGM-62, which could conceivably be generously included in the category, is actually just treated as a regular bomb and lacks a reflection stat.

 

Meanwhile, the HARM has a reflection stat of 0.05 and the Maverick sits at 0.063

 

This stat then needs to be compared against the reflection limit of the various SAMs:

0.02 for the SA-15

0.049 for the SA-10 and Patriot

0.1 for the Rapier

0.12 for the HQ-7

0.18 for the SA-2, SA-3, SA-6, SA-11, and Roland

0.22 for the SA-8 and Hawk

 

…and of course, the systems then have to have low enough a scan and lock-on time to see the target before it gets too close. This is what makes the SA-15 so annoyingly good at swatting weapons out of the sky: it has the lowest reflection limit in the (DCS) business, and a good lock-on time to match. The SA-10 is set to just about be able to detect most weapons aimed at it, but it is such a small margin that it struggles, and it has to go through a series of not-entirely-brief lock-ons before it can fire a missile that is bad at engaging short-range targets. So it's quite easy to make it not even bother trying to defend itself.

 

To “change that”, they would have to go through every bomb in the game (and there are… a few, let's say) and identify a reasonable, preferably well-sourced, RCS that can be abstracted into this internal reflection value, and then also preferably match that against reports of the system being used that way. It's not a major technical issue, but a pretty significant research, balance, and testing one.

[Wdigman]

Does the Doppler effect change the RCS value. A HARM is probably moving faster then a GBU 12 so the SAM can see a missile better than a bomb. In 1991 we saw on CNN Patriots shooting Scud Missiles out of the sky. Fast forward to 5 or 10 years ago (not sure when) and Israel's Iron Dome can shoot down incoming mortar shells.

 

For armor to evade bombs it would be better if the AI would know that if a jet gets within a mile or two of its position is to start moving or use smoke screens to conceal itself. Use terrain  or trees to hide vs just sitting there in the open. Laser weapons should not work if a tank or SA15 launcher moves into a wooded area or in between buildings if in an urban environment.

 

Bet this can be done in the mission editor using triggers routs etc to hide mobile units better.

 

 

[Northstar98]

On 4/5/2021 at 1:52 PM, BIGNEWY said:

It very much depends on RCS values, if you have data that shows a particular weapon system can intercept a particular weapon system please share it with us in a PM if you need to.

As with what Tippis said, bombs and unguided rockets are just classes of weapons that DCS systems just will not engage - they don't have a reflection limit defined so they're invisible to anti-aircraft units.

You can even see this when things like the SA-15 which will try and shoot down APKWS rockets and low observable glide bombs (such as JSOW) but won't do anything against unguided munitions that in some cases are a lot larger and aren't designed to be low observable - which doesn't make sense.

On 4/5/2021 at 2:36 PM, Wdigman said:

Does the Doppler effect change the RCS value?

Not in DCS it doesn't (from what I can tell), and I wouldn't have thought it would anyway, in DCS RCS is just one value, and it doesn't take into account aspect or configuration (unlike say, C:MO).

Quote

A HARM is probably moving faster then a GBU 12 so the SAM can see a missile better than a bomb.

A bomb though would still produce more of enough of a doppler shift to be detected by every RADAR defined in DCS - in DCS the radial velocity limit is usually set at ±10m/s or about 20 knots - which everything will travel faster than.

Edited January 12, 2022 by Northstar98
formatting

[dorianR666]

whats funny is that SAMs do engage the tiny APKWS but not 2000lb bombs

[Tippis]

Just wait until the first time you see IR SAM units trying to engage MLRS rockets. Then we can talking about things being… funny.

[Aigle2]

On 4/5/2021 at 2:52 PM, BIGNEWY said:

It very much depends on RCS values, if you have data that shows a particular weapon system can intercept a particular weapon system please share it with us in a PM if you need to. 

 

Without confirming data we are unlikely to make changes. 

 

thanks

To be honest I don't think a precise RCS value is necessary, because what is needed is a "gameplay" fix. 

The goal of such a change would be to stop an exploit about bombs and gliding bombs being more effective in a DEAD role than HARMS...
 

[Fri13]

20 minutes ago, Aigle2 said:

The goal of such a change would be to stop an exploit about bombs and gliding bombs being more effective in a DEAD role than HARMS...

 

Think about it how SAM systems would actually utilize their mobility and relocate themselves random times in periodic times (like every 10-15 minutes), or after each attack run etc. 

It doesn't take much to move behind a building or treeline for cover to wait a overfly, or wait inside forest and come out for a proper moment to launch etc. This of course on SAM systems that are highly mobile and not required to deploy complex systems to move. 

 

It would effectively render SEAD/DEAD missions far less possible to be done when the EWR maintains the threat positions updated to SAM systems near the area.

This so that even if the bombs and such wouldn't be detected in time, you don't have time to release them as you don't find the targets until it is too late. 

[ngreenaway]

On 4/5/2021 at 5:47 AM, Aigle2 said:

DCS has a core issue. Take a SA-15. It can intercept HARMs fired at it. Good. But...not the bombs.

In multiplayer, everyone uses JSOWs and GBUs to kill SAMs, because they can't detect and fire at them in response. Which make them better than HARMs to do SEAD/DEAD. This is not realistic, because from the SAM's radar perspective, a missile or a bomb is the same kind of radar contact. And because bombs are slower, it should even be easier to intercept them.

I don't think their is any major technical issue to correct this. So...could you ED change that ? 

yea, theres a fundamental flaw in that premise. a patriot wouldnt be able to engage a bomb. not all returns are classified and presented to the operator, and for good reason. for ED to allow it would be unrealistic

[LetMePickThat]

Any news on this front?

All point defenses are basically unable to engage bombs at the moment, making JDAMS or even GBUs more relevant than HARMs for SHORAD SEAD/DEAD missions... The only way around that I found for the various SAM mods I'm working on is to give the SHORAD system an optical sight with excellent performance to act like the radar when dealing with bombs, but that's far from ideal.

[BIGNEWY]

it will depend on the individual units modelled and if they are designed to engage bombs or not, again it all comes down to what RCS values they can or can not detect, if you think there is a problem with a particular unit please post a track example in a new thread and any unclassified evidence you have. 

thanks

[Mad_Shell]

1 hour ago, BIGNEWY said:

it will depend on the individual units modelled and if they are designed to engage bombs or not, again it all comes down to what RCS values they can or can not detect, if you think there is a problem with a particular unit please post a track example in a new thread and any unclassified evidence you have. 

thanks

The problem is that it does not depends on individual units radars, the problem is that RCS is not defined for bombs in DCS. They don't have an RCS at all, so you can have the very best radar in the world, it won't see bombs in DCS.

[BIGNEWY]

11 minutes ago, Mad_Shell said:

The problem is that it does not depends on individual units radars, the problem is that RCS is not defined for bombs in DCS. They don't have an RCS at all, so you can have the very best radar in the world, it won't see bombs in DCS.

Correct. 

Sorry I am ahead of you with our internal builds. RCS for bombs is being worked on, so for now I would say continue to be patient. 

[Badlego]

This sounds great! Are you also working on RCS values for artillery shells and Balistic missiles? The ground based phalanx CIWS is supposed to intercept mortar shells and i would love to see this in DCS as well. Thx

[BIGNEWY]

Just now, Badlego said:

This sounds great! Are you also working on RCS values for artillery shells and Balistic missiles? The ground based phalanx CIWS is supposed to intercept mortar shells and i would love to see this in DCS as well. Thx

Yes, there is a lot of work surrounding the implementation of the land based CIWS.

[Mad_Shell]

41 minutes ago, BIGNEWY said:

Correct. 

Sorry I am ahead of you with our internal builds. RCS for bombs is being worked on, so for now I would say continue to be patient. 

That's great news, thx for the reply BN!

[Dragon1-1]

Glad to see this being worked on. It's a bit odd to see APKWS and JSOWs being shot at (the former are tiny, the latter actually stealthy), while big ol' dumb Mk84 isn't.

[ngreenaway]

3 hours ago, Mad_Shell said:

The problem is that it does not depends on individual units radars, the problem is that RCS is not defined for bombs in DCS. They don't have an RCS at all, so you can have the very best radar in the world, it won't see bombs in DCS.

 

3 hours ago, BIGNEWY said:

Correct. 

Sorry I am ahead of you with our internal builds. RCS for bombs is being worked on, so for now I would say continue to be patient. 

Partly correct...and also, partly incorrect. A radar isn't going to detect something that lacks an RCS, however that's not the entire story. Just because a radar can see something , that doesn't mean the system will classify it as a threat or present it to the operators for consideration . Radars by necessity filter out a lot of stuff in order to only present probable targets, otherwise you'd see all kinds of crap -including ground traffic and spurious returns - on the scope and it would be much harder to discern what's engageable. 

Some of these filters include trajectory and speed. If it doesn't meet thresholds, it may get filtered out or classified as a different type of target. A bomb may come up as an "unknown " slow mover track type. The operator would have little reason to consider it a threat

 

Additionally , the fast mover that delivered the bombs makes for a much more compelling target.

 

RCS makes sense for CIWS like C-RAM, but outside of that I can honestly say that in the 10+ years I spent in air defense, never once did the idea of engaging a dumb bomb with a SAM come up

[BIGNEWY]

23 minutes ago, ngreenaway said:

RCS makes sense for CIWS like C-RAM, but outside of that I can honestly say that in the 10+ years I spent in air defense, never once did the idea of engaging a dumb bomb with a SAM come up

which is why I mention our work on the CWIS / CRAM, for any other system we would need evidence. 

[Roosterfeet]

I wonder how viable it would even be to implement a damage model for bombs? Would various AA weapons even penetrate the steel casing and would they detonate the bomb if they did? Info might be pretty scarce on that topic.

Edited December 15, 2021 by Roosterfeet

[Dragon1-1]

It's a hunk of steel with explosives inside, so that's pretty easy to estimate if you know how the AA weapon's warhead works. However, you don't have to cause an explosion to kill a bomb. Shearing off the fuzes will do. Pretty much anything can do it. 

Engaging dumb bombs with SAMs likely doesn't come up because it's pretty darn hard for a fast mover to get close enough in first place, assuming the SAM radar isn't dead (in which case you won't be shooting anything, anyway). IR SAMs, if overflown over their engagement ceiling, can usually just move out of the way. This is certainly not something that'll come up often, however depending on how things are set up internally, there might be some cases where the weapon isn't a typical bomb, but is still coded as one.

[jaylw314]

5 hours ago, ngreenaway said:

RCS makes sense for CIWS like C-RAM, but outside of that I can honestly say that in the 10+ years I spent in air defense, never once did the idea of engaging a dumb bomb with a SAM come up

Oh, come on, they did it in Tom Clancy's "Red Storm Rising"  That counts as unclassified material, right 

Actually, now I'm not sure if it was that book specifically, but remembering a Soviet SAM taking out some guided bombs in one of those Tom Clancy books from the 90's... 

[MrWolf]

On 4/5/2021 at 3:36 PM, Wdigman said:

Does the Doppler effect change the RCS value. A HARM is probably moving faster then a GBU 12 so the SAM can see a missile better than a bomb. In 1991 we saw on CNN Patriots shooting Scud Missiles out of the sky. Fast forward to 5 or 10 years ago (not sure when) and Israel's Iron Dome can shoot down incoming mortar shells.

 

For armor to evade bombs it would be better if the AI would know that if a jet gets within a mile or two of its position is to start moving or use smoke screens to conceal itself. Use terrain  or trees to hide vs just sitting there in the open. Laser weapons should not work if a tank or SA15 launcher moves into a wooded area or in between buildings if in an urban environment.

 

Bet this can be done in the mission editor using triggers routs etc to hide mobile units better.

 

 

RCS and doppler effect are completly different things.

 

RCS is related to the effective area of an object "as it was an antenna" (but for a reflector, so it doesnt absorb power into a load, but reflects it), well or as a reflector (which can be interpreted as an antenna). The power transmited by an electromagnetic field is caraterized by a Poynting vector which on short term describes power/m^2 [W/m²]. So the RCS of an object says whats the effective area that the object has in terms of absorbing the power of an electromagnetic field. The RCS already accounts for the dielectric and other things of the material so in short the RCS tells you how many power recieved by the EM field will be radiated back.

 

So power gets radiated through the medium losing intensity while traveling until reaches target which reflects as an RCS size ideal reflector and gets radaited back to the radar. You get squared times distance "atenuantion" (no that the field disipates on something (on air) but it gets evenly distributed on space so its intesity diminishes) and a reflection coeficient from the RCS.

 

Doppler on the other hand (very very simplified) its related to a frequency shift on the signal that you are transmiting.

 

RCS -> related with the power that you will recieve.

Doppler -> related with the "shape" of the signal that you will recieve.

 

Finally not for you:

 

WHY THE FUCK is DCS calculating the detection of an object by RCS at ANY GIVEN DISTANCE? Is this a joke? Detection is based on power recived wich depends on a static paramter RCS and a dynamic one the "attenuation" by distance which is proportional to 1/r⁴ which is huge.

 

As a more simple way of understanding that from this table:

On 4/5/2021 at 3:35 PM, Tippis said:

There are two slightly separate but related issues at play here.

 

One is that regular bombs simply don't have the “reflection” stat that sensors (including SAM search and tracking radars) use to identify and guide weapons onto target. Bombs aren't engaged by air defences because, from their point of view, they simply don't exist. The stat that would make them show up isn't there.

 

The other is that gliding weapons are internally defined as missiles, and those do get the reflection stat, but for whatever reason, gliding bombs are often given very tiny numbers.

 

The JSOW has a reflection of 0.05 to 0.0618, depending on variant (this is meant to be an abstraction of effective nose-aspect RCS in m², more or less).

The LS-6 has a reflection of 0.07.

The GB-6  has a reflection 0.1.

The BK-90 has a reflection of 0.4.

The AGM-62, which could conceivably be generously included in the category, is actually just treated as a regular bomb and lacks a reflection stat.

 

Meanwhile, the HARM has a reflection stat of 0.05 and the Maverick sits at 0.063

 

This stat then needs to be compared against the reflection limit of the various SAMs:

0.02 for the SA-15

0.049 for the SA-10 and Patriot

0.1 for the Rapier

0.12 for the HQ-7

0.18 for the SA-2, SA-3, SA-6, SA-11, and Roland

0.22 for the SA-8 and Hawk

 

…and of course, the systems then have to have low enough a scan and lock-on time to see the target before it gets too close. This is what makes the SA-15 so annoyingly good at swatting weapons out of the sky: it has the lowest reflection limit in the (DCS) business, and a good lock-on time to match. The SA-10 is set to just about be able to detect most weapons aimed at it, but it is such a small margin that it struggles, and it has to go through a series of not-entirely-brief lock-ons before it can fire a missile that is bad at engaging short-range targets. So it's quite easy to make it not even bother trying to defend itself.

 

To “change that”, they would have to go through every bomb in the game (and there are… a few, let's say) and identify a reasonable, preferably well-sourced, RCS that can be abstracted into this internal reflection value, and then also preferably match that against reports of the system being used that way. It's not a major technical issue, but a pretty significant research, balance, and testing one.

 

An SA-15 in DCS can detect an object with RCS of 0.02 so an ideal square reflector of 14,14 cm by 14,14 cm at any distance (because DCS detecion is based on RCS (WTF)). So a 14,14cm by 14,14cm reflector 10.000.000.000.000 km away from the radar can be detected by SA-15 DCS (hahahhaha). Or the same thing as saying that if you put the same square reflector infront of the antena of an SA-8 it won't be detected because i has an RCS lower than the detected by a SA-8 (imagine literaly blocking all the aperture of a horn antena and not detecing it because RCS lower than RCS of radar?¿?¿?)

Well i hope this information isn't correct because it's a very bad implementation of a radar and probably a lots of bugs come from this.

 

For you guys to understand: for a given RADAR with certain parameters, reducing the RCS of an object that we want to detect reduces the range at which will be detected. But reducing RCS doesn't make you invisible like some kind magic.

RCS it's like what size a visbile object has. You can see a fly if it's close to you, but if the fly is 5-10m away you won't be able to see it, say you cannot diferenciate it from the background.

In RADAR is the same but the term "differenciate from background" it's related with having a recieved power of an object higher than the noise level of the system. Which is related (just like with our vision) with the distance of the object to your radar and the size of the object (the RCS).

 

RCS is related to the material on which is reflecting the EM wave and MOST important the angle of incidence. If you notice stealth aircraft don't have angles of 90º from any prespective (well mostly from the side because aircrafts get radiated from the sides not from directly below).

Tail Wings straight up like F15 super bad (high RCS from sides), that's why f18 has tail tilted and why f22-f35-f117 too. Probably f16 has worse RCS than f18 (just guessing by it's tail).  Spcherical or cilindrical shapes worse than right angles, you get bad RCS from ALL directions, so A-10 motors are horribly bad on terms of RCS.

 

Then other factors that affect detection is doppler shift but this on terms on "signal processing". With doppler you can reduce your SNR needed to detect an object because you can discriminate from you transmited signal and the recieved one that something modified your pulse that you sent, so there is something there (VERY SIMPLIFIED).

Engines generate Very high dopler signatures !VERY HIGH!. So that's why also stealth aircraft have engine intakes on top of the aircraft and not below them (radar mostly look at them from a lateral below them).  F18 tries to hide its turbine blades from outside by doing some kind of curved intake. F16 something similar. A10 super bad turbine blades visible, spherical motors... . F117 turbine intakes on top and with bars to hide blades. etc...

Also take a look at JSOW its strange shape is to not have right angles (90º), well actually the RCS has to be reduced on front mostly its like and V shape but with diferent slopes:

 

Compare it to a TALD decoy (that you want to get detected). Right angles, probably made of a metal good reflector. :

 

 

Dumb bombs are cilindrical like so bad RCS but normally you only see the front so RCS not so big. Same applies for rockets (clindrical like). So as i said maybe when the radar detects the bomb it will be too late. But the RADAR WILL DETECT AT SOME MOMENT THE BOMB.

 

 

 

Edited December 16, 2021 by MrWolf

[Frederf]

Walleye is a bomb. Maverick is a missile. SAM won't engage the Walleye.