Anti-missile hit probability

[Zeebie (OP)]

So this keeps happening:



The stated hit chance is ~20%, but I will launch hundreds of missiles and not score a single hit.  Am I not understanding something about what "Chance to Hit" means?

[Jorgen_CAB]

Can you paste the design of those AMM, do you have at least 1 point of damage on their yield on them?

[Zeebie (OP)]

Sure, here it is. It has a size 1 warhead.

Vaccine III AMM (1490)    Speed: 38,400 km/s    End: 0.3m     Range: 0.7m km    WH: 1    Size: 1    TH: 473/284/142

[Kylemmie]

side note - Vaccine AAM. . . . . . thanks for the chuckle!

[Garfunkel]

Can you show us the full combat log? There should be a break down of things affecting ToHitChance

[Zeebie (OP)]

Can you show us the full combat log? There should be a break down of things affecting ToHitChance

How do I access the full combat log?  This is all I get in the events window.

[Iceranger]

Can you show us the full combat log? There should be a break down of things affecting ToHitChance

Sadly, the breakdown is no longer available in C#

[Iceranger]

So this keeps happening:



The stated hit chance is ~20%, but I will launch hundreds of missiles and not score a single hit.  Am I not understanding something about what "Chance to Hit" means?

How fast are the incoming missiles?

[Zeebie (OP)]

How fast are the incoming missiles?

60k. But shouldn't that be included in the calculation of chance to hit?

[TheTalkingMeowth]

Hmmm. With the attack missiles being faster than the interceptors, you have a serious problem; due to the way aurora handles increments, they may never intercept and get to make an attack roll.

But from what you posted, they ARE getting to make an attack roll. It's just missing.

[Iceranger]

How fast are the incoming missiles?

60k. But shouldn't that be included in the calculation of chance to hit?

It should be, speed, agility, and ECM/ECCM should all be included in the displayed hit chance, based on tests in 1.11. That's why I was asking for the speed of the missiles so I can hopefully narrow down what went wrong.

Based on your AMM's specs, and displayed lowest hit chance, the enemy missile should be around 67600km/s. Is that the case? Do you notice any mentioning of ECM levels on the incoming missiles?

[Zeebie (OP)]

It should be, speed, agility, and ECM/ECCM should all be included in the displayed hit chance, based on tests in 1.11. That's why I was asking for the speed of the missiles so I can hopefully narrow down what went wrong.

Based on your AMM's specs, and displayed lowest hit chance, the enemy missile should be around 67600km/s. Is that the case? Do you notice any mentioning of ECM levels on the incoming missiles?

Yes, that speed is correct. I don't remember seeing any ECM announcement.

[Iceranger]

I don't seem to be able to reproduce the issue in my test setup.

AMM:

Code: [Select]

Missile Size: 1.0000 MSP  (2.50000 Tons)     Warhead: 1    Radiation Damage: 1    Manoeuvre Rating: 129
Speed: 20 000 km/s     Fuel: 150     Flight Time: 2 minutes     Range: 2.84m km
Cost Per Missile: 3.13932     Development Cost: 314
Chance to Hit: 1k km/s 2580%   3k km/s 860.0%   5k km/s 516%   10k km/s 258%

Target:

Code: [Select]

Missile Size: 3.00 MSP  (7.500 Tons)     Warhead: 0    Radiation Damage: 0    Manoeuvre Rating: 10
Speed: 40 000 km/s     Fuel: 1 675     Flight Time: 18 hours     Range: 2 556.3m km
ECM Modifier: 60%     ECCM Modifier: 60%
Cost Per Missile: 9.00     Development Cost: 900
Chance to Hit: 1k km/s 400%   3k km/s 133.3%   5k km/s 80%   10k km/s 40%

The hit chance would be
25800/40000 - 60% = 4.5%

Event log:


So the displayed hit chance is correct (with rounding), and the AMMs actually hits something.

Of course, AMMs being slower than the target means there is a non-negligible chance of interception failure. But once the interception is successful, the hit rate seem to be expected.

I had multiple suspicions on why this could happen, but it seems the above disproves all of them:

• ECM/ECCM is not displayed in the event log (never happened in previous versions), which is disproven by the log showing the theoretical hit chance correctly
• The displayed hit chance is 100x (at one point this was a bug), which is disproven by the same observation
• There is hidden mechanics on missile hit chance if missile speed is lower than target speed, which is disproven by my AMMs actually hit something

[Jorgen_CAB]

Could it just not be that the ASM have an ECM rating of 30 and therefore the chance of hitting become less then zero and that this simply is not displayed in the to hit chance even though it probably should?

At least this seem like the most likely explanation.

I think ECM should be emphasised in the to hit as it can be very decisive at times.

[Iceranger]

Could it just not be that the ASM have an ECM rating of 30 and therefore the chance of hitting become less then zero and that this simply is not displayed in the to hit chance even though it probably should?

At least this seem like the most likely explanation.

I think ECM should be emphasised in the to hit as it can be very decisive at times.

In my example, the target missiles have ECM on them, and the displayed hit chance correctly considered it.