[RESOLVED] BIG BIRD not detecting and counting of SA-21B missiles is off

[Blast33]

Strange behavior of the S-400 (SA-21B) DB v499 Build 1307.6

The BIG BIRD D does not detect the B-52s at any stage (.sav included).
EMCON is active. Sensors say active radar. But it does not see the targets. The Cheese Board & Grave Stone do.

When I change the amount of 40N6 missiles from 64 to 8 but the count says 40?

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The amount of missiles which will fire at targets still are 8 which is good. Only the visible counting is off.

When I add a single SA-21B TEL, the total amount is 12x 40N6 missiles the count says 44? At the same time the amount of SA-21a missiles is moving correct from 32 to 4. So that counting is working fine.

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To sum-up:
1. The Big Bird is not working as advertised.
2. The counting of only the 40N6 is not logical and gives confusing amounts, while the simultaneously changed 48N6DM are correct.

S-400 strange behaviour.zip

(17.28 KiB) Downloaded 17 times

[bsq]

When I change the amount of 40N6 missiles from 64 to 8 but the count says 40?

The amount of missiles which will fire at targets still are 8 which is good. Only the visible counting is off.

When I add a single SA-21B TEL, the total amount is 12x 40N6 missiles the count says 44?

32 in your magazine
8 or 12 in your tels
Gives you the 40 or 44 you are seeing

[Blast33]

I missed the Magazines indeed, thank you.

Remains the Big Bird which is not working.

[Deserere]

Hi Blast33,
I think that the Big Bird works as expected.
the LOS is less then the radar nominal max range (the one you can see with the circle on the map).
Once the B-52 come closer is detected as it should

[bsq]

Big Bird antenna height from data base set at zero feet. Terrain height at the Big Bird location is 10 feet amsl.
B-52's at 36000 Feet Amsl

Radar horizon calculates out at 237.02nm

Actual pickup in that save is at 194nm for Big Bird vice 210 for Grave Stone and Cheese Board.

Something not quite right with the pickup on the BMR set (Big Bird) which has a scope range of 325nm from the database vice 210 for the Grave Stone and 220 for the Cheese Board. Big Bird should see it first as far as I can work out using the RF calculator tools online.

[Dimitris]

Right, so the problem was that the Big Bird was placed right in the middle of an urban sprawl, and the antenna was obscured by the surrounding culture-height. This was why it was able to detect the B-52 only as it came closer.

Now, we realise most scen author don't pay attention to land-cover type when placing sensor facilities, so we isolated this effect to its own specific realism, option, which is disabled by default (see: https://www.matrixgames.com/forums/view ... 9#p5084579 ).

With this feature disabled, detection happens reliably at long range as expected.

Resolved in Build 1307.9 .

[Blast33]

Sorry but I don't agree that I placed the Big Bird in a urban sprawl. And that this is the cause for the performance dip of the Big Bird radar

For CMO the landuse is this case is the same for the Big Bird as the Grave Stone and Cheese Board radar.
If I hover with my cursor over the location, it says mixed forest and the same with the S-400 unit. So performance wise they should act the same.

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And in real life it looks like this. (S-400 north, Big Bird in the south) BTW the positions are arbitrary placed just for the test.


How does CMO reason that this is a urban sprawl?

What does make a difference is that the S-400 unit is placed at 72ft elevation and the Big Bird at 10 ft. And.. the mast hight of the Big Bird is in the DB 0 feet! and that of the #1937 SAM Bn S-400 is 39 meters!
This looks like cheating for the S-400. I know a Grave Stone can be placed on a mast but it is optional.

And I turned the terrain effects off and the Big Bird detects the B-52 (big RCS) at 185Nm instead of 199Nm with terrain effect turned on. Now done in Build 1307.9. I do not think it is resolved.

Could you help me how to explain this situation, why you think this is urban sprawl so I can work with it in the future (besides the DB issues).
Thank you.

[Dimitris]

Sorry but I don't agree that I placed the Big Bird in a urban sprawl. And that this is the cause for the performance dip of the Big Bird radar

For CMO the landuse is this case is the same for the Big Bird as the Grave Stone and Cheese Board radar.
If I hover with my cursor over the location, it says mixed forest and the same with the S-400 unit. So performance wise they should act the same.

Clipboard02.jpg

And in real life it looks like this. (S-400 north, Big Bird in the south) BTW the positions are arbitrary placed just for the test.

How does CMO reason that this is a urban sprawl?

I stand corrected, it's indeed placed in a forest instead of urban area. This provides a 5m "culture height" (see here: https://www.matrixgames.com/forums/view ... 1&t=393513 ), which again effectively obscures the Big Bird radar, as I previously explained.
As you pointed out, the S-400 unit avoids this issue thanks to its higher mast-height value, which easily clears the forest skyline.

What does make a difference is that the S-400 unit is placed at 72ft elevation and the Big Bird at 10 ft. And.. the mast hight of the Big Bird is in the DB 0 feet! and that of the #1937 SAM Bn S-400 is 39 meters!

This looks like cheating for the S-400. I know a Grave Stone can be placed on a mast but it is optional.

The mast height values in the DB represent the typical deployed systems. For systems that are meant to be used in elevated masts, we provide a matching mast height to reflect this. The S-400 has a major anti-cruise missile task so its radar components are frequently seen in elevated masts. Big Bird has a more general "airspace surveillance" role so it is rarely (/never?) seen in elevated position, with the exception of some fixed radar towers like this around Moscow: https://www.ausairpower.net/PVO-S/19Zh6 ... wer-1S.jpg . (They are placed in towers to avoid being obscured by the local forestry).

The 0 value is an error (I have asked the DB team to review mast-height values for non-elevated sensors in facilities), but until now it was of minor importance as blockage at the sensor source point was not considered. With the addition of the skyline mechanics this becomes more important, if that feature is enabled.

And I turned the terrain effects off and the Big Bird detects the B-52 (big RCS) at 185Nm instead of 199Nm with terrain effect turned on.

That difference is small enough that it could be borne out of a number of different reasons (e.g. differences in re-scan time, OODA-loop reaction etc.) rather than simply be the result of having the terrain effects enabled/disabled.
Your original report demonstrated the B-52 not being detected until it was at a significantly closer range.

[blu3s]

Are there any future plans to be able to have the mast height values modified (between a minimum and maximum height for example) in land facilities? Like the altitude selector for aircrafts for example

When a sensor is added to a facility, what height does it take?

Thank you

[Dimitris]

Are there any future plans to be able to have the mast height values modified (between a minimum and maximum height for example) in land facilities? Like the altitude selector for aircrafts for example

This is not on a plan ATM.

When a sensor is added to a facility, what height does it take?

Until DB v499, all sensors used the unit's mast-height value (IIRC this is listed in the DB).

From v499+, there is now the option for per-sensor mast height. If this is present the sensor uses this value; otherwise it uses the unit's overall mast-height value as before.

[Blast33]

Thanks for the explanation Dimitris.

[KnightHawk75]

From v499+, there is now the option for per-sensor mast height. If this is present the sensor uses this value; otherwise it uses the unit's overall mast-height value as before.

Thanks, helpful to know it does fall-back to unit value if not defined.