LMC goes crazy when laser hits own missile after launch

[FalcoGer]

This happened to me a few times and I find it somewhat annoying.

When I have a target stable in my crosshair with LMC enabled I keep on firing muh lazor, as one does to do a LOBL SAL hellfire shot. Then when the missile comes off the rail, it sometimes happens that the laser hits the missile. This causes an immediate jump in target range from several thousand meters to a couple tens of meters. The LMC now thinks the target which before had a relative motion is suddenly much closer and the TADS needs to move at light speed to keep up with it. Suddenly the laser points all the way left, I loose the target visually, the missile goes stupid.

Is this realistic? If so, how am I supposed to do a LOBL shot with LMC on? What should I do differently? It happens rarely enough that it's not a massive deal, but often enough to be really annoying when it does happen.

Edited June 29, 2022 by FalcoGer

[ricktoberfest]

The LMC needs to be manually moved doesn’t it?  Not gonna lie, haven’t played the Apache much since latest update (and since Viacom doesn’t work with it) but the LMC only moves if you move the joystick, it’s not actually tracking the target like a point track would. I think you might have a different problem than you think is happening. 

[FalcoGer]

LMC keeps relative motion to the target. For that it needs accurate ranging. Jumps in ranges will result in jumps in angular speed of the tads. Which is also why you need reasonable ranging before you first turn it on.

Edited June 29, 2022 by FalcoGer

[Floyd1212]

I think this must have happened to me last night.  I had the target lased and LMC was stable.  After I launched, I see the white smoke on the TEDAC from the missile passing in front of the TADS and next thing I know the TADS is panning hard right and to the sky.

[Marine03]

     I've had this happen several times since the latest patch to OB. I originally thought I mashed the wrong button or slewed the TDC, but then it happened a second and third time during the same mission. Forgot to add that I was also using the LMC in each instance.

[FalcoGer]

So is that correct? Or is there some sort of filter, perhaps an averaging, or something going on to prevent single, erroneous readings like that from affecting the targeting? Surely someone at boeing must have thought of that, or fixed it after it happened in testing/combat.

[Frederf]

Most laser rangefinders use specific parts of the return, first return, last return, average, etc. and some like M1 Abrams can choose which return to take. The laser spot isn't small enough that it hits the missile and only the missile.

[FalcoGer]

11 hours ago, Frederf said:

Most laser rangefinders use specific parts of the return, first return, last return, average, etc. and some like M1 Abrams can choose which return to take. The laser spot isn't small enough that it hits the missile and only the missile.

That is not what I asked about. I asked if there is some system in place that would prevent a single, bad measurement from messing up the aim. The apache's default range is first reflection, but can be swapped to last. I guess I could give that a try as a workaround, but still not what I asked for.

[Frederf]

There might be some state machine limiting LMC displacements in range. What I'm saying is the idea that the missile could even contribute to any sort of range data in the first place (even if wanted) might be ridiculous itself.

[Floyd1212]

21 hours ago, Frederf said:

The laser spot isn't small enough that it hits the missile and only the missile.

We are talking about when the missile comes off the rail, and passes in front of the TADS, 10m in front of the aircraft.  This is when the LMC goes nuts.

For example, you are lasing a target at 5km with LMC enabled, and then for a split second the laser reads a return at 10 meters, then again at 5km when the missile has passed.

At least, that is the working theory...

[Hobel]

@FalcoGer
I think I could reproduce the problem with F16, Unless the behaviour is intended .

I have taken F16 because the problem should be related and it is easier to show that way.

 

 

Apache LMC .trk Apache LMC2.trk

[Scaley]

On 8/3/2022 at 4:00 PM, Frederf said:

There might be some state machine limiting LMC displacements in range. What I'm saying is the idea that the missile could even contribute to any sort of range data in the first place (even if wanted) might be ridiculous itself.

Unfortunately in DCS laser spots appear to be literal point objects, with no physical dimension. If you are precise enough you can range and/or designate a telephone wire. Clearly that isn't like a real laser, but it's what we currently have in DCS. I guess previously with fast-jets it hasn't mattered much, although to some degree it's been annoying in the Ka-50 forever.

Edited August 6, 2022 by Scaley

[Floyd1212]

This is still a thing...

Can a SME chime in to verify this is/isn't an issue in the real aircraft?

If it isn't working as intended, can this thread be moved to the Bugs and Problems forum?  There are track files attached above.