LDIRCM (and DIRCM) can involuntarily affect multiple missiles at the same time

[tripod2008]

@Big_Djck_Sergey

just because missile has veered off course, due to induced target tracking errors, or induced guidance command errors due to Countermeasures, or for whatever other reason, does not mean that the target is no longer in the Seekers FOR!

Once a missile goes ballistic after the lock-on is broken, positional error and pointing error will accumulate, as the relative position of the target will change so it can’t just look in the prior direction and know the target will be there, because it won’t be, it’s position in the scene will have changed.

@Big_Djck_Sergey

and the Seeker is steered and stabilized automatically, so that the Target Centroid will be in the center of missiles FOV.

It’s not though, it’s the Seeker’s pointing angle rate that is held constant, there is no need for the target to actually be held in the center of the IFOV of the seeker of a staring seeker since there is no null to drive it into, there is no fixed requirement of have it centered.

@Big_Djck_Sergey

the Target Centroid is re-calculated in real time and the whole Missile’s Seeker is again turned so that the newly calculated Target Centroid will be again in centered missiles FOV.

There is no need for it to be centered, it can be anywhere in the image since the scene is effectively continuously polled for updates independently (slight difference in how CCD & FPA work under the hood but is mostly immaterial to the point).

@Big_Djck_Sergey

At this point, the Seeker may be aligned with missiles Velocity vector or not

No PN declares that the seeker’s look angle at launch must be held constant to achieve intercept.

For the simplified 2D case:

where;
the scalar an is the acceleration perpendicular to the missile’s instantaneous velocity vector
N is the proportionality constant generally having an integer value 3-5 (dimensionless)
λ is the line of sight rotation rate
V is the closing velocity.

There is no mechanism for the look angle to change.

@Big_Djck_Sergey

a Deviation is calculated and a guidance command is generated proportional to that of the Deviation.

You are getting confused about which loop does what in a two loop tracking system, The Seeker tracking the target and Autopilot providing instructions to the control surfaces are separate loops.

@Big_Djck_Sergey

The Missile is steered so, that its velocity vector will become Co-Axial with it it’s LOS

No it is steered in such a way that the Angular rate of change of the seeker is driven to zero

@Big_Djck_Sergey

the missile’s seeker will cointinue to be Gyro Stabilized and will continue to point in the direction of the last TC, meaning last valid silhouette it used for solving said TC.

No, As an example with the Maverick , this always occurs in the Terminal stage of the intercept (target estimator box exceeds 75%, of the FOV) where the target has become a near uniform return across the FOV due to being in the last few seconds of flight Control surfaces are commanded to maintain their current deflection angle to provide intercept.

[Big_Djck_Sergey]

@DevilO6

You do know that LDIRCM does not just inject fake course data using the laser, right?

I have already mentioned and explained that above in the tread. It seems to me you have been reading beteen the lines.

For the seeker, it is full of IR radiation, from its perspective, it is right at the IR source, that causes false signals to be send, and the whole system fails.

Depends on the Seeker type and how the Centroid is being calculated.

Even if the target is inside the missile FoR, it would need to be inside the FoV, when the seeker desaturates, and at that point the missile can be anywhere. The gimbal will not be kept at the target, as there is nothing to follow.

Absolutely not true.

You dont know if there will be nothing to follow if the seeker becomes desaturated.
It depends on how the missile was fired, what aspect, what was the trajectory of the target, did the target change course while the seeker was blinded?

The gymbal will be stabilized in its last orientation before the seeker was blinded, as I explained before.
The gymbal is gyro stabilized and even without a valid Centroid will remain gyro stabilized in its last orientation. That is the basic principle of operation of the missile. Please, do your own research on basics of IR missiles and basics of the guidance loop.

I use modern Imaging seekers in the examples, since they are what present the most interest, and they are the ones that DIRCM and LDIRCM systems will have to work against.
@tripod2008

Once a missile goes ballistic after the lock-on is broken, positional error and pointing error will accumulate, as the relative position of the target will change so it can’t just look in the prior direction and know the target will be there.

That is not true, as I explained above.

Let me give you an example:

1)A missile is fired rear aspect at a Target aircraft.
2)The missile approaches the targets and its seeker gets dazzled by LDIRCM.
3)The seeker remains pointed and gyro stabilized towards last target location in 3D space
4)During the period of time the seeker was dazzled/blinded/saturated, the Target did not change trajectory signifficantly. The Target Remained in the Seekers FOV (or FOR for those seekers that will attempt to re-scan after loss of target silhouette)
5)Later, for whatever reason, the Seeker is no longer dazzled by the LDIRCM (for example malfunction in the LDIRCM system).
6)The seeker sees the bright thermal signature of Targets Engines
7)Valid re-acquisition is achieved
8)The missile continues normal operation and normal tracking of the target

Furthermore:

can’t just look in the prior direction and know the target will be there, because it won’t be, it’s position in the scene will have changed.

It doesnt ‘look into’ prior direction. It already is gyro stabilized and pointed towards exactly where the target is supposed to be, based on last known trajectory, as long as that is possible (seekers’ Gymbal Limits), and attempts a re-acquisition.

This is called Memory Track Mode.

It’s not though, it’s the Seeker’s pointing angle rate that is held constant, there is no need for the target to actually be held in the center of the IFOV of the seeker of a staring seeker since there is no null to drive it into, there is no fixed requirement of have it centered.

Absolutely wrong again. At this point I think you are trolling may be? Keeping the target silhouette centered in the seeker’s FOV is fundamental for reliable missile tracking and guidance, because:

1)Modern imaging seekers track a Target Centroid, which is the intensity-weighted center of the target in the sensor image.

2) If the target drifts toward the edge of the FOV the image may become distorted due to lens effects.

3) If the target drifts toward the edge of the FOV the seeker may lose lock entirely if the target or part of it leaves the FOV.

You are getting confused about which loop does what in a two loop tracking system, The Seeker tracking the target and Autopilot providing instructions to the control surfaces are separate loops.

I know that too.

No it is steered in such a way that the Angular rate of change of the seeker is driven to zero

Read everything again carefuly. I skipped the Guidance solution details

There is no mechanism for the look angle to change.

Again nonsense. Example: If the Target maneuvers and changes trajectory, the look angle changes.

The look angle is dynamic and always changes whenever the target moves relative to the missile.

Explanation:
A missile has a mechanical and control mechanism to change the look angle, and that’s exactly how it keeps the target centered in the seeker FOV even when the target moves. Let me break it down:

Look angle is angle between the missile’s velocity vector (or body axis) and the seeker boresight (line of sight).
It is absolutely not fixed, because targets can move, and the missile may need to observe them from different directions.

How the Look Angle Changes Mechanically

1. Seeker Gimbal System
   The seeker head is mounted on a 2-axis gimbal (pitch & yaw).
   By rotating the gimbal, the seeker can point off the missile’s body axis.
   This changes the look angle relative to the missile velocity vector.

2. Mechanical Limits
   Each seeker has a maximum gimbal deflection, for example ±60° for AIM‑9X.
   The look angle cannot exceed these physical limits.

The Look Angle Changes Dynamically:

The tracking loop continuously measures centroid error
The error is the Target Centroid Position minus the FOV Center

This error is used to turn the gimbal, which rotates the seeker to reduce the error. The Seeker’s boresight is therefore always centered with Centroid.

When the target moves, the gimbal rotates → look angle changes in real time.

Then, the look angle is fed to the guidance computer:
Proportional Navigation uses LOS rate, which depends on changes in look angle over time.
The missile generates steering commands to reduce LOS rotation at intercept. (the formula you copy pasted from somewhere without understanding).

And finally:
The Look Angle at launch is almost never constant.

Because:
The seeker must initially gimbal toward the target, creating a look angle other than zero.
During launch the target is rarely perfectly aligned with the missile’s velocity vector.

That’s that.

[tripod2008]

@Big_Djck_Sergey

1)A missile is fired rear aspect at a Target aircraft.
2)The missile approaches the targets and its seeker gets dazzled by LDIRCM.
3)The seeker remains pointed and gyro stabilized towards last target location in 3D space
4)During the period of time the seeker was dazzled/blinded/saturated, the Target did not change trajectory signifficantly. The Target Remained in the Seekers FOV (or FOR for those seekers that will attempt to re-scan after loss of target silhouette)
5)Later, for whatever system the Seeker is no longer dazzled by the LDIRCM (for example malfunction in the LDIRCM system).
6)The seeker sees the bright thermal signature of Targets Engines
7)Valid re-acquisition is achieved
8)The missile continues normal operation and normal tracking of the target

This entire scenario depends critically on the geometry between the target and the missile, the same thing could effectively happen with an unguided rocket fired on a perfect trajectory to intercept the target, since it it doesn’t move a hit is assured.

Remove step 4 from this and it all falls apart, don’t forget that even with an IMU error still exists so corrections and estimations of target state won’t be perfect.

@Big_Djck_Sergey

It doesnt ‘look into’ prior direction. It already is gyro stabilized and pointed towards exactly where the target is supposed to be, based on last known trajectory, as long as that is possible (seekers’ Gymbal Limits), and attempts a re-acquisition.

But how does the missile know as to which exact frame the jamming began to be injected (slow rise flares for example defeat IRCCM)? You can’t just assume that the Predicted Trajectory of the target simply has no error in it prior to the onset of jamming.

@Big_Djck_Sergey

Keeping the target silhouette centered in the seeker’s FOV is fundamental for reliable missile tracking and guidance

No, no it’s not for imaging seekers. Look especially at the B-17 intercept footage, it’s not in anyway centered in the field of view of the seeker. Why would it matter where an electronic gate is in reference to the FOV?

- YouTube

[Big_Djck_Sergey]

But how does the missile know as to which exact frame the jamming began to be injected (slow rise flares for example defeat IRCCM)? You can’t just assume that the Predicted Trajectory of the target simply has no error in it prior to the onset of jamming.

Of course it “knows”, since it loses the ability to determine a Target Centroid for whatever reason (in the above example due to application of countermeasures.)

Has valid Target Centroid - Has valid Tracking solution of said Centroid - Steering commands are normally generated
No valid Target Centroid - Switches to MTM and attempts re-acquisition.

This entire scenario depends critically on the geometry between the target and the missile, the same thing could effectively happen with an unguided rocket fired on a perfect trajectory to intercept the target, since it it doesn’t move a hit is assured.

The analogy with unguided rocket is wrong. Don’t twist my words to fit your argument.
If you fire an ungided rocket at a moving aircraft on a ballistic collision trajectory, and the aircraft changes its own trajectory, it will not hit.

Again, for the last time:
The target aicraft could have changed trajectory, but still be in Targets FOV (or FOR for more advanced missiles that will scan during MTM), therefore a valid re-acquisiton can be achieved.

You can’t just assume that the Predicted Trajectory of the target simply has no error in it prior to the onset of jamming.

That is true, you can’t. You do what you can to guide the missile on the best trajectory, based on the information you have (or had, prior to successful ‘jamming’).

(slow rise flares for example defeat IRCCM)?

There are different types of flares. After missiles with UV flare discrimmination were introduced, flares that glow in both the UV and IR spectrum were also introduced on aircraft. That is why early Lamp based IRCMs were so successful when used together with such flares.

if a missile is fired rear aspect, you would prefer to have a flare that will burn long enough and also emmit in both spectrums, to increase the chance of the flare discrimination algorithm to consider the falre to be a valid target.

No, no it’s not for imaging seekers. Look especially at the B-17 intercept footage, it’s not in anyway centered in the field of view of the seeker. Why would it matter where an electronic gate is in reference to the FOV?

It is, I already explained you why above.
Using AGM-Walleye for comparison or example is absolutely wrong.

Walleye is a TV-guided, unpowered glide bomb, not a high-agility missile using Proportional Navigation. Its flight path is fundamentally energy-limited and ballistic/glide in nature. Because it has no propulsion and limited control authority, temporary image displacement of the tracked contrast point does not imply tracking failure — it simply reflects glide dynamics and proportional correction lag.

Therefore, observing a Walleye video where the tracked point appears off-center does not demonstrate how an IIR missile behaves under similar conditions. The control architecture, energy state, and guidance law are fundamentally different.

And finally while it does have a Gymbal mounted Seeker:

1)It does not have the large, high-speed, wide-angle gimbal authority of modern IIR AAM seekers.
2)Its stabilization and tracking bandwidth are much lower.
3)It is not designed for extreme off-boresight, high-G maneuver tracking.

So while it is mechanically steerable, it is not comparable to modern gimbaled IIR missile seekers in agility or tracking precision.

[tripod2008]

@Big_Djck_Sergey

and the aircraft changes its own trajectory, it will not hit.

Of course but as per step 4 it does not;

@Big_Djck_Sergey

4)During the period of time the seeker was dazzled/blinded/saturated, the Target did not change trajectory

So in such a scenario as you have constructed it will hit the target. No?

@Big_Djck_Sergey

or FOR for more advanced missiles that will scan during MTM

Such as? I’m not aware of any that lack a Two way datalink (and so correlate the seeker LOS with informed target position ) that even attempt retargeting.

@Big_Djck_Sergey

Using AGM-Walleye for comparison or example is absolutely wrong.

Why? The methodology is the same, between EO and FPA seekers. Hell even in the excerpt you hear the engineer state:

“at that point it’s a Sidewinder”

@Big_Djck_Sergey

And finally while it does have a Gymbal mounted Seeker:

1)It does not have the large, high-speed, wide-angle gimbal authority of modern IIR AAM seekers.
2)Its stabilization and tracking bandwidth are much lower.
3)It is not designed for extreme off-boresight, high-G maneuver tracking.

So while it is mechanically steerable, it is not comparable to modern gimbaled IIR missile seekers in agility or tracking precision.

Ok cool so it’s not to spec. for an Air to Air missile, ok Sure. How does that impact the underlying mechanics being nominally similar; Thus somehow not being able to be applied to both?

[Big_Djck_Sergey]

I said:

4)During the period of time the seeker was dazzled/blinded/saturated, the Target did not change trajectory signifficantly.

Which means there has been some trajectory change.

Why? The methodology is the same, between EO and FPA seekers. H

The Walleye tried to keep the target Centered with Boresight, it just cannot always achieve that perfectly due to trajectory, aerodynamic, energetic and inertial constraints.

I explained why. Please read with comprehension.

Again:
The AGM-62 Walleye does try to drive the tracked point toward its internal reference (center of its tracking frame). The guidance loop generates steering commands proportional to image displacement. (nothing new or extraordinary here)

However, it unpowered glide bomb, with large mass, limited control authority, has slower control response and tracking bandwidth,flies an energy-limited ballistic/glide trajectory.

That is why It cannot always steer ideally and cannot correct angular error as aggressively or as quickly as a powered air-to-air missile, that has thrust vectoring and signifficantly less Moment of Inertia.

As a result, the tracked point may temporarily appear off-center, even though the system is still converging (just more slowly).

“at that point it’s a Sidewinder”

Yet it cant be used against planes due to what? Again:
-Energetic and Aerodynamic constraints, Guidance Solution, (and probably narrow Gimbal and other limits related to target tracking).

As you can see, at 33:58 in the video, the Tracking point is kept in the Center without issue. In later launches the Bomb was probably launched from a non-ideal release envelope, and was having hard time correcting itself. Wind can also be another cause.

[tripod2008]

@Big_Djck_Sergey

Which means there has been some trajectory change.

Wouldn’t “no change”, still fall within the bounds of No Significant change? there is no way to quantify “some” in this context other than it being insufficient to impact the outcome.

There issue here is that the statement lacked a minimum value and as this is notional scenario you probably shouldn’t exactly quantify things.

@Big_Djck_Sergey

The Walleye tried to keep the target Centered with Boresight

Please go back and review exactly what was said in the video and the footage of the B-17 intercept,

The change in position of the target gate informs pointing error of the Seeker, and so in moving to correct that error introduces angular rate to the autopilot which it then countermands via the control section so in effect it is held constant.

@Big_Djck_Sergey

it just cannot always achieve that perfectly due to trajectory, aerodynamic, energetic and inertial constraints.

We’re talking methodology here, not particular capabilities Please stop trying to muddy the waters with talk of insufficient performance.

Beside how fast is a stationary B-17 causing the seeker to move? Once a proper Intercept trajectory is assumed all it needs to then account for is perturbations in the missile’s flight path not any sort of target movement.

So why is it off center if it was supposedly required for the system to function properly.

@Big_Djck_Sergey

Yet it cant be used against planes due to what?

I have literally provided footage of it tracking a B-17, The seeker is evidently perfectly capable of doing so.

I didn’t know a an aircraft stopped being an aircraft if it was stationary, have you Tried informing the missile of this obvious contradiction.

[Big_Djck_Sergey]

@tripod2008

The video you provided:
At Time:
1:44
23:43
31:19 (and the following few minutes)
33:56
You can clearly see that while the weapon glides towards the target, the tracked point remains centered in the camera’s FOV.
Are you satisfied now?

So why is it off center if it was supposedly required for the system to function properly.

I already explained to you why. Read again with comprehension. If you don’t like the answer, you can DYOR (do your own research on this) and will come up with the exactly the same answers.

You are comparing apples to oranges, and are not satisfied that they taste different.

Beside how fast is a stationary B-17 causing the seeker to move? Once a proper Intercept trajectory is assumed all it needs to then account for is perturbations in the missile’s flight path not any sort of target movement.

You dont know if the weapon was released at ideal launch envelope, if there was crosswinds or turbulence, or any other external factors.
As you can see at the times i gave you above, the target point remains centered.

Also some of the footage has clearly been recorded with External video camera from the plane’s monitor, due to the flashing scan lines (interlacing). Which can explain why on some of the footage the target does not appear to be centered.

For example the footage at 34:47 is clearly recorded with a misaligned external camera (interlacing and vignetting are present).

at 22nd minute the person explains exactly why the camera has to be gyro stabilized.
also 26:49

More explanations by the people 30:48 in the video.

The change in position of the target gate informs pointing error of the Seeker, and so in moving to correct that error introduces angular rate to the autopilot which it then countermands via the control section so in effect it is held constant.

I explained to you already that the Walleye’s seeker is Gymbal mounted. It is not affixed stationary to the missile body. The people in the video explain why it must be Gyro Stabilized.

For the FINAL TIME, here is step by step operation: (I will no longer argue with you about this anymore):

Step 1: Target moves in the seeker’s view

The Walleye has a gimbaled TV seeker in the nose.
The seeker has a ‘target gate’ (or tracking window) on the image.
If the target drifts inside that window (due to aircraft release, wind, or initial motion), the system detects the displacement — this is the error.

2)Seeker gimbal moves to correct error

The gimbal actively turns the seeker to bring the tracked target back toward the center of its field of view.
This is the seeker ‘following the target.’
At this point, the target may still appear slightly off-center, because correction is not instantaneous.

3. Gimbal motion turns the seeker relative to the missile

The seeker gimbal moves to reduce the pointing error, and keep the Target Centered.
This motion does not directly move the missile, it just changes where the seeker is pointing.

4)Autopilot uses pointing error to generate control commands

The autopilot (FCS) takes the pointing error from the seeker and converts it into commands for the control surfaces.
The control surfaces adjust the bomb’s angular rates so that thebomb’s velocity vector rotates to reduce the LOS angular error. This forms a feedback loop: seeker measures angular displacement >> guidance converts it into commanded angular rates >> control surfaces generate rotation >> seeker sees reduced angular error.

Now you can see why the Missile (in this case the Walleye bomb) tries to keep the Target always centered in the Seeker’s boresight. in my previous posts I have explained why this is fundamental to Guided weaponry Imaging Seekers.

So at this point I don’t know what are you arguing about and what kind of convincing you need?

I didn’t know a an aircraft stopped being an aircraft if it was stationary, have you Tried informing the missile of this obvious contradiction.

You know very well that I meant a flying and actively maneuvering aircraft.

Edit (Addition):
Here you can see accurately modelled operation of the AGM Walleye

- YouTube

[tripod2008]

@Big_Djck_Sergey

You can clearly see that while the weapon glides towards the target, the tracked point remains centered in the camera’s FOV.

Sure, but that is up to the pilot as to placement of the gate in the scene (it is not actually required in any way as shown), which can be accomplished by either

Taking one’s hand off the throttle and manipulating the hand control (depending on airframe it may be the RIO that uses a rewired Bullpup or Radar hand control, not the pilot) to provide fine alignment to superimpose the gate with the target. While also flying the aircraft.

Or use the gate as a reference to fly the aircraft like a Snowplow and capture the target when in alignment.

One is much easier to focus on for an aircraft with a single crew member especially while being potentially shot at, and keep a plane flying while trying to release ordnance.

Do not mistake Test articles for the AGM-62, with production Walleyes don’t forget this program pioneered Contrast seekers.

The easiest way to tell them apart is that the Gate is either composed of two sets of either white or black parallel lines, also the lack of the FoR indicator (square that the image gate is super imposed over)

@Big_Djck_Sergey

I already explained to you why. Read again with comprehension. If you don’t like the answer, you can DYOR (do your own research on this) and will come up with the exactly the same answers.

@Big_Djck_Sergey

and will come up with the exactly the same answers.

Did that particular Walleye not consummate the intercept? it’ certainly didn’t look like it was struggling at all, it didn’t fall short.

@Big_Djck_Sergey

I explained to you already that the Walleye’s seeker is Gymbal mounted.

Can you even quote where i said it was fixed? This was never at issue.

@Big_Djck_Sergey

tries to keep the Target always centered in the Seeker’s boresight

It does not, it attempts to keep the gate in a fixed position in the field of FoV; this is not necessarily as demonstrated the center of the FoV. This would be different for something like the AXX-1 TCS camera on the F-14 for example due to the use of the Line of Sight for correlating the Radar’s antenna train angle along the line of bearing of a contact.

@Big_Djck_Sergey

You know very well that I meant a flying and actively maneuvering aircraft.

Sure, but my point is that if it is within the system’s capability to track it doesn’t matter, since motion of the target or missile both result in relative movement of objects the scene.

@Big_Djck_Sergey

Here you can see accurately modelled operation of the AGM Walleye

Do I really need a simulation when I’ve presented actual test & combat footage? Also as the Walleye has been revised many times over it’s service life who is to say what had happened in the intervening years in terms of upgrades, due to being a modular card based there were many revisions to hardware, and potential configuration that may function very differently, also as the ER/DL had a datalink capability some way to independently slew the gate and seeker was not needed.

The baseline Walleye likely lacked any ability to freely gimbal the seeker away from boresight prior to release, which is why the gate is what is moved to select a target, not that it is modeled in WT.

@Big_Djck_Sergey

I will no longer argue with you about this anymore

Good, I thank you for your concession.

[Big_Djck_Sergey]

@tripod2008

Sure, but that is up to the pilot as to placement of the gate in the scene (it is not actually required in any way as shown), which can be accomplished by either

That is true, but after launch, during guidance, for any modern Imaging seeker guided Air to Ground weapon, the gyro stabilized seeker will turn so that it tries to keep Target is centered in relation to boresight. It is important that the edge of the contrast target silhouette does not move too close to the edge of the image, (explained why above, and will explain again bellow why it is so important for Air to Air missiles). May be the Walleye was not so precise or “demanding” of keeping that area as tight as possible in relation to the Image’s center?

I also gave you two very plausible explanations why in some of the footage the target does not appear centered.

Do I really need a simulation when I’ve presented actual test & combat footage?

In the Actual test and combat footage you provided, it is clearly seen that the target is properly centered in the image at times:
1:44
23:43
31:19 (and the following few minutes)
33:56
Even if those were earlier prototypes of the actual production model, it is clearly seen that the developers of the Walleye understood that the gate should be kept pretty much in the center of the image.

At other times, the image is recorded with external, camera, not properly centered in relation to the display the pilot was looking at (for obvious reasons, not to block his view).
You can clearly see the induced interlacing, vignetting and on some shots even part of the pilots display is shifted to the side and not captured fully. (Example at 34:42 in the video). So we cant tell where exactly is the gate in relation to the full frame.

During the targeting of the plane on the ground, the image does look looks as if it was recorded straight from the onboard receiver. (there is no signifficant interlacing or other optical signs that show it might have been recorded from external camera).
So I cannot tell for sure why the Target appears so far away from the center of the frame.

Even if:

It does not, it attempts to keep the gate in a fixed position in the field of FoV; this is not necessarily as demonstrated the center of the FoV

Even if that is true for the Walleye, the Seeker would be gyro stabilized in such a way so that to keep “keep the gate in a fixed position in the field of FoV” as you said.
Which is not wrong, but ideally the target must not be allowed to drift too far from the center of the frame, let alone get anywhere near the edges. That is especially important for Air to Air missiles. (explained why above in previous message and again with tracking details bellow).

Using the Walleye as an example to precisely understand the guidance principle of modern imaging Air to Air missiles is on one hand good, because it explains the basics of contrast target tracking of early generation Imaging seekers, how the developers of that principle cam up with it and why the Seeker has to be moiunted on a Gimbal and be able to turn in relation to Missile’s /bombs’s body.

But on the other hand ‘treacherous’, since it can lead to misunderstanding when it comes to more modern systems.

For the centering ‘issue’ Walleye, it is not crucial: The target is stationary, the moment of inertia of the Walleye is large, it flies very stable and must not execute high G maneuvers. The target does not deploy countermeasures (flares) to try to shift the target point within the frame. While on Air to Air missiles, there is a risk of the Target centroid to get rapidly updated to a new location on the frame, due to (e.g.) flares becoming intermitently part of the Tracked Target Silhouette. So if the target Silhouete is close to the edge, and the Gimbal turns the whole seeker in a way that part of the Silhouette or the whole silhouette is lost from FOV (due to the Centroid shifting position rapidly and inducing unfavorable gimbal commands), the tracking of the target can be lost.

That is why the target silhouette for Air to Air missiles should be ideally kept centered as much as possible, because it proportionaly reduces the chances of the above mentioned loss of track happening.

Good, I thank you for your concession.

And I too. It is a great technical discussion and I am sure many will find it interesting.

May be we should make another thread some day about Laser Guided Air to Ground bombs/missiles? Different types of Laser guidance, inner details of beam-riding guidance etc. etc…

Later generation AGM missiles, including US ones, also follow that principle, as the need to reliably and precisely destroy even moving targets was prioritized:

- YouTube

Another video where the target is keps in the center of the image. It is even seen how it drifts around and the gymbal immediately corrects itself.

- YouTube

[tripod2008]

@Big_Djck_Sergey

It is important that the edge of the contrast target silhouette does not move too close to the edge of the image

The thing is that the Walleye tracks edges, not centroids. Where even the AGM-65A tracks the centroid of the contrast target in the gate.

@Big_Djck_Sergey

the target must not be allowed to drift too far from the center of the frame, let alone get anywhere near the edges.

Even if it was to, the SAP-HE warhead equipt WGU-10 Maverick (?-65F?(unconfirmed but likely) or -65G) variants can for example transition a track to a Correlation Track on either axis independently(aka.Synergistic track) should a target exceed the FoV. They basically use the rest of the scene to maintain relative bearing to the scene to continue to prosecute an intercept.

The use case for this is attacking a large surface combatant, which can easily be many times longer than it is high.

@Big_Djck_Sergey

The target is stationary

Nothing requires it to be, only that as a large mass glide bomb with a warhead designed to deal with infrastructure (it uses a novel Linear Shaped Charge) its not optimized for tactical targets, the same way a Maverick’s heat warhead isn’t optimal for dealing with fortifications, but it still could have a sufficient effect.

@Big_Djck_Sergey

The target does not deploy countermeasures (flares) to try to shift the target point within the frame

This is more so an issue of CCM circuitry and less the seeker specifically, if I was going to point to a contemporary (alternate ) Electro-Optical seeker I’d point to the AIM-95, but I don’t have much info on it.

[Big_Djck_Sergey]

The thing is that the Walleye tracks edges, not centroids. Where even the AGM-65A tracks the centroid of the contrast target in the gate.

I know that.

They basically use the rest of the scene to maintain relative bearing to the scene to continue to prosecute an intercept.

That is a valid point, however unapplicable in Air to Air missiles due to obvious reasons (the sky is 'blank").

The use case for this is attacking a large surface combatant, which can easily be many times longer than it is high.

That is absolutely true.

Nothing requires it to be,

Aerodynamic and inertial limitations of the Bomb itself can be a limiting factor, along with type of target to be tracked, its speed and etc. etc.

This is more so an issue of CCM circuitry

Of course. For the purpose of explaining to those not familiar with how the tracking works I have omitted that from the ‘equation’. Since I was explaining the technical reasoning behind that design choice.

Here is a better visualization I made, applicable to Air to Air missiles:

[tripod2008]

@Big_Djck_Sergey

Here is a better visualization I made, applicable to Air to Air missiles

Regular flares can be discriminated from a real contact though the use of Radial Rate filter since they rapidly decelerate due to aerodynamic drag, having no propulsion and being ejected in a different direction to that which the target is flying.

Assuming that aircraft were limited to less than ~14G (there are reports of an F-14A surviving an extended 13G excursion without overstressing the airframe) you can further refine this with an IMU on board to let the missile recover range rates as well.

- YouTube

So as soon as you get to IRCCM that the AIM-9M is known to use this falls apart.

Even so a Centroid may be separately generated if the spectral return appears to be separate islands. There is no requirement that only one centroid be generated, but only one used for guidance at a time.

[Big_Djck_Sergey]

Regular flares can be discriminated from a real contact though the use of Radial Rate filter

@tripod2008

So as soon as you get to IRCCM …

This is an oversimplified Visualisiation of the basic tracking principle of a Contrast target and does not take into account any IRCCM or advanced seeker algorithms (as I have noted in the picture itself.)

[tripod2008]

@Big_Djck_Sergey

This is an oversimplified Visualisiation of the basic tracking principle of a Contrast target and does not take into account any IRCCM or advanced seeker algorithms

Sure but for contemporary systems, especially for those of staring imagers in an Air to Air application, basic efforts make this a non issue.

[kedrigern]

@Big_Djck_Sergey

Once again, the mirracle ‘HoJ’ to save the day.

hmmm, i wonder what that blinding light thats targeting my seeker from the direction of my target is… must have been the wind.

HoJ isnt a miracle, its a significant function to prevent the funny little laser beam from making a missile useless.
The current issue with LDIRCM is that is functions less like “a beam” and more like a force field. Now i personally really like using CLAWS or NASAMS in general with 9X missiles. And against helis, ive also tried to fire the 9Xs at different release angles (thanks to the launcher being angled and able to be rotated) in quick succession.
The end result is the same. The game does not care about “bro you dont get it, its not a pin point line but a beam” and instead its a complete zone in which no matter how fast in succession or from which angle the IR missile gets veered off from its course.
Now personally i wouldnt give a shit too much even if its unrealistic to have force field on helis as that is atleast one way to survive an increasingly more long range IR SAMs IF the system was actually modeled with a built in cooldown to simulate having to switch targeting from one to the other missile. But thats not the case.

Additionally, when it comes to the beam, incomplete jamming (i.e. not completely on the missile) is not effective enough to mask the target, so even smaller changes position can still let a modern IR (IIR) SAM to continue guiding in without even considering the other options the missile has at its discretion like the HoJ, continuous DL, etc.

Now the most simple reason why things are how they are is because its easier to implement it as a zone denial rather than a standalone module that has to target missiles individually and that the implementation could either just not work with the engine we have ingame (its already a miracle it can function with most modern equipment ingame) or wouldnt be effective at all (just look at MUSS implementation).

From purely gameplay perspective in context of fairness over poorly implemented mechanic while still being based in reality, the LDIRCM systems should have a built in cooldown of 0.2-1s (adjustable for balance) between missile interceptions, that way overwhelming a helicopter with IR missiles is a valid counterplay that forces the helicopter players to play smart while still offering a blanket of protection instead of current situation where a fire and forget loaded helicopter can fly unobstructed against both IR SAM AD and ARH SAM AD (different topic) with only SACLOS being the only valid and under-performing counterplay outside of a single SPAA ingame.

[Armen_Lozone]

geeeeeeeeez, is this guy still going?

[UNN_Daedalos]

@Armen_Lozone

which, as far as i know, most manpads do not have imaging infrared seekers. in assymetric warfare, militaries can expect the use of Aim-92, Mistral, Igla, Anza/HN-5 or QW-2. but mostly stingers. and those dont have imaging seekers

Afaik only Mistral 3 is IIR, although it’s not really a manpad technically speaking, but considered this way in game

MISTRAL%20family%20brochure%20-%20WEB.pdf

[Armen_Lozone]

Yeah at that point it’s more like the ty90 than a manpad heh…

[MommyDommyEnjyr]

@kedrigern

Now the most simple reason why things are how they are is because its easier to implement it as a zone denial rather than a standalone module that has to target missiles individually and that the implementation could either just not work with the engine we have ingame (its already a miracle it can function with most modern equipment ingame) or wouldnt be effective at all (just look at MUSS implementation).

thats how DIRCM/LDIRCM is currently modelled for helis, it doesnt take into account fuselage blockages or really anything blocking the laser like the rotary blades. there is a reason on every heli to date that has DIRCM/LDIRCM its either on the sides or below (never on the top) but hey lets have it counter missiles directly above it in completely unrealistic circumstances because gaijin cba coding properly fixed zones.

Dont even get me started on its ability to effect multiple missiles at once contrary to ANY source that states its only capable of deflecting 1 missile per module or per zone being detected in, then when you couple this with helicopters absolutely atrocious radar cross section values being non existent it makes even ARH missiles a chore to hit because any slight drift in hover will send any ARH missile away.

Helis shouldnt be getting DIRCM/LDICRM till they actually model the damn thing correctly, give rotary blades the PROPER radar cross section signature so they cannot just multipath like its a fly in the wind