[FIXED B998.11] BIG bug in AMRAAM missile

[Ancalagon451]

Some days ago I read a comment in the forum about weapons datalinks for ARH AAMs not being correctly modeled, and it has been nagging me since then. Today finally decided to run a little test to put my mind at rest and I found something ugly here.

The attached scenario is a very simple test run with an AMRAAM missile already in the air (launched via a plane deleted just after firing) and a high speed bogey (MiG-31 in afterburn) put on a maximum deflection course, plus a ground radar in the missile's side.

When you run it you'll see the missile going in a straight trajectory, as it should due to the lack of weapons datalink, but when it arrives to its kill box and switches to active seeker; IMMEDIATELY makes an almost 90 degrees turn to put itself in a perfect pursuit trajectory to the bogey. Which in the moment of the missile going active, was both out of boresight and range.

The missile employed is an old AIM-120A so no CEC shenanigans here (the ground radar was choosen at random) and, unless it is missile specific bug, this could to be a big flaw in the whole ARH engagement model.

So please give it a try and tell me that I've done something wrong here.

Ancalagon

[Dimitris]

Thanks for the heads up. We are looking into this.

[Amnectrus]

This may be related, it's something I've noticed on and off for quite a while and this made me get around to trying a proper test:

The AIM-9M doesn't have a datalink at all. It needs to acquire the target with its own seeker before it's launched, and after it's launched, it should be completely fire-and-forget, as far as I know. Even if the launching aircraft is destroyed, the AIM-9M should continue to home in on its target. However, in the game, if the firing side (not just the launching platform, but all friendly units) loses track of the target, the AIM-9 goes dumb and starts flying straight. As soon as any friendly unit reacquires the target, the AIM-9 starts guiding again.

In the attached test scenario, I have two Blue F-15s in trail, spaced 30 miles or so apart, with a Red Su-27 flying directly across the nose of the first one. It's night, and the F-15s don't have IR sensors, so the only contact is with radar. I've manually fired an AIM-9M from the first F-15, and immediately moved the F-15 about 20 miles away and turned its radar off, and that's where the scenario starts. Within a couple seconds of unpausing, the Su-27 contact will be lost (countdown appears under the icon) and the missile will stop guiding. If you then turn on the trailing F-15's radar, the missile will resume guiding, making a sharp turn to follow the contact, even though no datalink should be present. I tried it with the AA-10 Alamo B IR-guided missile and the AA-11 fired from the Su-27 against the F-15s in the same circumstances, and got the same result: the missiles only guided when Red side had contact with the targets.

It's not something that happens very often in the game, because normally there are at least a few units that see an enemy with some kind of sensor, but when it does happen it's pretty surprising... Thanks for looking into it!

[Cik]

i've seen this also with A-G weapons. weapons will get in a weird tail-chase with a contact that's moving around due to uncertainty. IIRC, most GPS/INS bombs should basically just fly to the desired point of impact without any ability to change course when released.

maybe the same issue?

[Dimitris]

Possibly, the more example saves we have the better.

[Amnectrus]

INS/GPS guided weapons should only allow you to drop them when the target's location ambiguity is basically zero (i.e. you have a point target, not a target-uncertainty-area). I haven't personally seen weapons like JDAMs get into tail-chases or maneuver at all, but I have frequently seen weapons with seekers change their course, sometimes radically, in response to target-uncertainty-areas changing. For instance, that happens a lot with antiship missiles under heavy jamming, and AFAIK that's Working As Designed, unless there's some kind of tie-in with the mystery datalink effect here where the missile is getting position updates from friendly units and not data from its own sensor...

However, I did do a test with AGM-65D IR Maverick missiles, and found that they do behave in the expected fire-and-forget manner and will continue to home on their target even after the friendly units are no longer tracking it. The attached scenario was saved immediately after firing a Maverick at a group of tanks, and the launching plane was moved away. When you unpause, the contact will be lost (countdown will appear under the target) but the missile will still hit. So Mavs appear to be working correctly...

[Dimitris]

ORIGINAL: Amnectrus
INS/GPS guided weapons should only allow you to drop them when the target's location ambiguity is basically zero (i.e. you have a point target, not a target-uncertainty-area).

This sounds like a wholly separate issue, if you have observed this then please make a new thread on it with a suitable save. Many thanks!

[Dimitris]

Fix for OP issue appears to be working well, will be include don the next public update release.

[jforceno1]

My online download is telling me to "insert a second disk". It a online download.....what give?

[Ancalagon451]

will be include don the next public update release

Will it be included in the Kurils Command LIVE DLC?

Ancalagon

[Dimitris]

ORIGINAL: jforceno1
My online download is telling me to "insert a second disk". It a online download.....what give?

Hi, are you sure you're posting in the correct thread? Thanks!

[Dimitris]

ORIGINAL: Ancalagon451

will be include don the next public update release

Will it be included in the Kurils Command LIVE DLC?

Ancalagon

Yes, that is the plan.