Tank Fire Control Systems

[PhilippRauch 0]

how about a bit "faking" it? as long as the barrel point in the general direction and elevation, nobody will ever realize the shell got a slight "flightpath correction" on its way out of the barrel via script. These scripts will cover whats needed on math for different tanks, ammunitons etc... so only rangetables need to be made, no brainmushin lodpushing... he? could work?

or about doing it totally in scripts, the optics are the weapon now, the barrel is only driven by animation states from the scripts together with the chechz barrel axis memory points. when the now optic weapon fires its round it will come out of the now, correctly elevated barrel, elevation precisely calculated by the scripts. basically its a new animation source driven from the scripts of the sight.

both ideas should get rid of the necessecty to align painfully sight to barrel etc...

the first can work for any tank, since its script driven, only adaption or additions to the ammunitions data file is necessary.

the second will need model and config work.

[.kju 3244]

My personal opinion is that this project could be reactivated as

a community project.

Unfortunately NWD didn't include any copyright or details if his

work can be modified.

That said, he didn't seem the guy to be eager to keep his work

all for himself. After all it is more a standard how to make a tank

addon.

From what I know, NWD was contacted by several people over the

time. He said back then that he will not come back to ArmA.

So much water has gone done the river meanwhile. So IMO

it is okay to turn this project into a community project while

maintaining the credits and spirit of NWD.

It is a very complex system and requires in depth knowledge.

So again only this is approached in a good open spirit by a group

of capable people I can see this get successful.

[mr.g-c 6]

Quote[/b] ]From what I know, NWD was contacted by several people over the

time. He said back then that he will not come back to ArmA.

This is correct. I was also one of which tried to contact him over Youtube some time ago, but he seems to just disappeared from all Arma stuff.

[ravendk 25]

I really hope you guys can ressurect this project. Propper firecontrol systems is really something that would benefit all.

All the best to you guys and good luck.

[kuIoodporny 45]

My personal opinion is that this project could be reactivated as

a community project.

Unfortunately NWD didn't include any copyright or details if his

work can be modified.

That said, he didn't seem the guy to be eager to keep his work

all for himself. After all it is more a standard how to make a tank

addon.

From what I know, NWD was contacted by several people over the

time. He said back then that he will not come back to ArmA.

So much water has gone done the river meanwhile. So IMO

it is okay to turn this project into a community project while

maintaining the credits and spirit of NWD.

It is a very complex system and requires in depth knowledge.

So again only this is approached in a good open spirit by a group

of capable people I can see this get successful.

I greatly appreciate that idea I was waiting for NWD's response for about 4 months to release updated stuff.

[PhilippRauch 0]

How about BIC_ i.e. Bohemia Interactive Community Teamtag? Like OFPEC_ILS or such, now theres a BIC_MFCS (MBT Firecontrolsystem).

I propose to see NWDs work as a template, just like the multiple turret vehicle and others released some time ago... Just totally rebuilding the system and not just converting/adapting the scripts NWD wrote originally. BTW, did he use BIS T72 and M1A1? If so doesnt it fall under the agreement BIS has with anybody using their MLODs? If so there is even less problem regarding who to ask. Still a compleat rebuild is the best solution, also because we can avoid possible caveats early on and maybe add even some more functionality to it.

I think about destructable Optics and such (Which are also a common target for snipers btw). The Tanks i envision have the FCS, destrucable optics and turretweapons i.e. a hit might kill the optics and turretmg but maybe still the maingun is working in manual mode with coax optics... And if your unit is class engineer, or maybe a new class "Mechanic", it can remove damaged stuff and replace it with new ones from supply or even loot another, more damaged Tank for its parts...

Basically all is possible in theory and i personally see no big difficulties, except the time needed to finish it in time.

maybe BIC is not possible for legal reasons but then BICteam is nice too me thinks...

[mr.g-c 6]

I really hope you guys can ressurect this project. Propper firecontrol systems is really something that would benefit all.

All the best to you guys and good luck.

Exactly! And even more since in Arma2 we wont have this really neat feature either (according to interview Ivan Buchta).

So the work is not "wasted" when Arma2 is out.

[colligpip 0]

I wonder if mando could adapt his missile system to work more like the optics of a tank. He has done well for gun camera targeting systems.

[kuIoodporny 45]

Yeah, that would rock.

But should we start the thing from the very beginning? I don't think it'd be wise nor needed...

[PhilippRauch 0]

With "from scratch" i meant more the planning, so we can foresee problems in future or on how adapt the system to be suitable for any addon, or not ...

Even if its just changing all Addonmaker Tags.

[sakura_chan 9]

A good place to start would be to make a list of things that need to be done. From what I've seen looking through the model is that it should be quite easy to fit this system on any tank. The only hard part is figuring out how to add new weapon trajectories to the system. The actual position of the sight on the turret doesn't seem to be a huge deal, and i don't think it has to be especially lined up with the gun. I think Arma automatically lines up the sight with the gun at a certain range, and NWD's addon slightly alters the view based on turret speed, elevation, range and target lead. Just throwing ideas out there, but wouldn't it be possible to calculate the trajectory from the ammo's config? Or have some way of recording a shell's trajectory and outputting the arc graph into similar data that he originally used? It would be sweet to have this in ACE...

List:

1. Get it working in MP

2. Figure out new trajectories

3. Look into the manual turret system he mentioned

4. Complete the 'battlesight' feature?

5. Add flir (setaperture 0.06) or nvg system

6. Bug fixes and AI testing

keep adding if you have ideas!

[kuIoodporny 45]

List:

1. Get it working in MP

2. Figure out new trajectories

3. Look into the manual turret system he mentioned

4. Complete the 'battlesight' feature?

5. Add flir (setaperture 0.06) or nvg system

6. Bug fixes and AI testing

keep adding if you have ideas!

1. Gotcha -> all we needed to change is to use 'player' instead of '_player', it was done half year ago.

3. Todo -> add 2 extra script controlled anims... if doable at all.

4. Todo -> range setting and go. There's nothing so complicated I guess?

5. Gotcha -> see my VNV / maybe ACE has something similar?

6. Gotta catch 'em all   plus it shouldn't bother AI.

So the trajectories are the most important thing to do.

About breakable sights - could we use glass damage there? (+ remove standard and add high dispersion weapons)

[PhilippRauch 0]

I think it uses rangetables, cheops used something similiar with his artillery. it even comes with an tutorial about it. it shows also a way to come up with the needed formula, maybe it helps.

With a little script putting out the result via armalib to a database will help to avoid lots of copy&paste doing it cheops arty way.

But having Rangetables is maybe a good idea anyway to make indirect fire easier (as Dialog viewable on map). i.e. a call for indirect fire on coordinates x,y the commander will only need to find out on map the correct heading and distance, he looks up the barrel elevation for the needed distance and ammo and fires his rounds... something like that.

[.kju 3244]

Can everyone who is interested in actively contribution in the

development please send me a PM with his skype acc.

Thank you.

Let's see if we can this get started as an open community project

as part of our new development portal.

[NonWonderDog 0]

Hi guys.

Yeah, I haven't been around here for a while, and I haven't done much of any work on this in the interim.  I fully support any attempt to turn this into a community project.

I'll try to answer questions about how this works and where I was taking this, but I've forgotten a lot of it by now.  I didn't really have a to-do list written down either, which was one of the reasons this just fell off my radar--I just didn't know what to do with it.

These are the parts of my to-do list that I do remember, though:

Trunnion tilt correction.  This was #1 on the to-do list for FOREVER, but it's just so spectacularly complicated that I didn't know where to begin.  In short, my code currently only gives accurate values if you are on flat land.  If you are 90 degrees to a slope, the results will be somewhere between "close enough" and "garbage."  (The code currently assumes that the turret ring is both perpendicular to gravity and in-plane with the target's movement.  If the tank is tilted, everything will be wrong.  The real fire control systems correct for this.)

Rangefinder logic fixes.  When you switch rangefinder logic from first-return to last-return, you shouldn't have to lase the target again.  This just needs some code-flow changes that I was too lazy to make.

Manual range control for the TPD-K1 gunsight.  You should be able to push a button and scroll the range up or down.  This isn't a separate mode, but something you can do at any time.  Lasing a target would override whatever you've scrolled the range to.

Machine gun range tape for TPD-K1 gunsight.  There should be two sets of numbers for the TPD-K1 range tape -- one on bottom for the main gun, and one on top for the coax.  Instead of using the rainbow sight for the coaxial, you should be able to set the FCS to HEF mode (the "O") and manually set the gunsight range using the upper row of numbers on the range tape.  Then you can use the main aiming chevron to point the coax (the windage will be way off, though).  This is more than a little bit esoteric, but I wanted to add it after I had manual range control in.

Manual battlesight range for the M1A1 gunsight.  You should be able to push a button and open a dialog that lets you type in a new battlesight range to override the default 1200 meters.  I don't remember if this range is per ammo type or not, but I believe that it is.

Illuminated reticle for the TPD-K1.  Flip a switch, it turns red.  Not hard.  The simple way to do this would be to change all the optics textures to red instead of black and add the night-time illumination flag, or whatever it is.  I didn't do this to start because the optics textures were originally HUD overlays, which don't have this flag.

TPN3-49 or similar night sight for the T-72.  This would be an entirely new sight mode, and it would have to be activated by the night-vision key (it would use the normal light-amp implementation in the game, as that's what the real sight is).  Entering a tank would have to give you night-vision goggles if you don't have them, and leaving the tank would take them away (if you didn't have them before).  The default night-vision overlay would have to be removed, and default (foot) night-vision would have to be handled with HUD overlays, much the same way as the tank reticles were in version 0.1 of this mod.  I hadn't started on graphics or models or anything for this, and I can't find any references for the reticle any more.  I can't even remember if I had any pictures of the reticle besides this one. (EDIT -- scratch that, I have fairly detailed info in my T-72A manual.  Available on request.)

FLIR mode for the M1A1 sight.  This needs new, but similar, graphics.  That means new models, animations, etc.  Ideally it would be green, rather than black-and-white... but whatever is fine.

Auxiliary sights for the M1A1.  It's probably not possible to implement these correctly, but the textures would be easy enough.  These aren't really critical.  At all.

Find a way to fix the gunner's periscope forward on the T-72.  It doesn't have any elevation in real life, and it shouldn't have any in this mod.  I have no idea how to do this, or if it's even possible.  My idea was to have a second set of aiming animations in the model that moves exactly opposite the normal aiming animation, but I couldn't figure out how to toggle such an animation on and off.

Emergency turret operation.  Real tanks have hand cranks to rotate the turret if power is lost.  ArmA has a turret damage class that disables turret rotation and gun elevation.  By adding new control points and animations, and a custom animation-handler script (there are several in this mod), you can map keyboard keys to rotate the turret even if normal turret rotation and gun elevation are disabled.  This would be very easy to add... but it might screw up the AI if you were to use it when the turret was still operational.  This would be fun to screw around with, if nothing else.

ATGMs.  New sights with SACLOS navigation for the missiles, with proper laser receptor FOV and whatnot.  Yeah, this was never going to happen.  But it's possible.  Probably.

New gunsights for a BMP, T-64B, T-80, Stryker, Bradley, Challenger, or whatever I had planned.  I have spotty references for all of these, so ask if you need them.  

That highlights the other reason this died, though: it's a demoralizingly huge amount of work just to find references, and half of them are written in Russian.  My Russian is about 1st grade level, and almost worthless for reading these things.  I'll look though my references to see if I have anything useful to you guys and I'll... probably only give them out by email or Rapidshare or something, because I don't want my Filefront account shut off for violating a Russian copyright (HA!) or for some idiot claiming that I'm conducting espionage by posting twenty year old declassified operating manuals.

Here's some general points of what I remember of how the script works:

Each tank model must be specially modified for the sights.  This doesn't just involve putting sight models in front of the player viewpoint at the right distance (simple trigonometry), though.  The models need extra memory points added for turret rotation, gun elevation, gunsight component rotation, viewport rotation, viewport translation (for multiple gunsights--I'm not sure if I finished this feature), and probably something else I'm missing.  The model also needs to have its animation definitions edited to add new turret rotation and gun elevation animations, as well as every animation related to the gun sight.  The script will use these animations to automatically lay the gun or move the viewpoint or change the sights or whatever is needed.  This is miles better than in version 0.1, which brute-forced things by rotating the whole tank for lead (an AI driver would keep the chassis from moving) and moving the shell as soon as it's fired for elevation.  Version 0.1 didn't require the model changes, though.

The ballistic definitions are from the output of the bullet tracking code in Kronzky's portable target range.  I fired a shell with the turret perfectly level, and the script saved the flight time and shell drop to various ranges.  (I then put this in an excel spreadsheet to compare with actual ballistics data, and I kept tweaking shell drag and shooting again, and tweaking shell drag and shooting again, and tweaking shell drag and shooting again until I got what I wanted.  I only figured out that I could have used a MATLAB script and a quadratic drag equation for this AFTER I'd finished the ballistics.)  The FCS script uses this data for some fancy interpolation using the range the "laser rangefinder" returns.  

Rangefinding works by shooting seven instant-hit zero-damage special-effectless bullets in a hexagon (with one in the middle) and finding the range to each one.  Depending on range logic, either the furthest or nearest range will be returned... unless that range is greater than maximum range or less than minimum range.  You'll have to edit this script to change the laser spread for each new sight.  

The turret tracking script is a loop that runs constantly whenever tracking is required.  This is continuously in the M1A1, but in the T-72 it only starts tracking when you hold down the button (and stops tracking when you let go).  There are actually two threads here. (I'm sure there's a good reason for this.  Probably.)  The first thread runs every frame and continuously interpolates turret slew rate from weapondirection and writes it, along with vehicle velocity, to a vehicle variable.  The second thread runs every .1 seconds and appends each of the current rotation and translation speeds to a vector. If the vector has more than 1.5 seconds worth of entries, the oldest entry is deleted from the vector.  When requested, all the values of the vector are averaged together, and the result is the output.  This all works mostly through voodoo, not proper planning and code design, and I won't be able to describe it any much more detail than that. (I think I name all the old elements "deleteme" and then subtract "deleteme" from each vector.  Not exactly proper vector handling, but it doesn't seem to result in a huge, destabilizing memory leak.  I think.)

That's probably the other reason I abandoned this: most of my code is voodoo.  I'm not really a programmer.  What programming I do do is usually in MATLAB.  I have no idea if my code has to be so convoluted and absurd.  For example, this gibberish in the turret tracking code compensates for the turret rotation applied by the FCS during operation, so that the FCS can know how much the turret is rotating (minus FCS influence) so it can decide what rotation to apply to the turret:

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">// cancel sight lead feedback

if (!isNil {_pvehicle getVariable "NWD_FLOATING_LEAD"}) then {_tazimuth set [0,(_tazimuth select 0) - 360/6400*(_pvehicle getVariable "NWD_FLOATING_LEAD")]};

Gah.  There's too much here to describe all at once.  If you have questions about the code, I'll try to answer them.

One more thing, though:  after I'd written most of this script, I found out that you can read animation state from any vehicle animation, including turret rotation.  The turret tracker could probably be very much simplified if you used the turret animation state instead of my current implementation.  You could get rid of that gibberish expression above, for one thing.  Doing this might make the needed trunnion tilt compensation harder, though; I don't know.

[kremator 1065]

It's great to see you back NonWonderDog !  You have included a LOT of informaton here.

With ARMA2 on the horizon is there any way that you can continue with your addon?  Pretty please with bells on.

It has proved to be one of the most popular addons and indispensible for us tankies !

[TAO] Kremator

PS Reading current animation state is probably what is needed for other FCS (like on manned vehicles that could use Mando Gun/Mando Missiles). Information on how you do that would be cool for our coder gurus !

[colligpip 0]

great to see Non wonder dog back hopefully this addon can see some improvements.

[PhilippRauch 0]

I still think its good to rebuild the whole, its still possible to copy&paste snippets from the original addon. And THANKS to NWD to take time to reply so thorougly.

How about those two ideas to solve the trunnion tilt correction?:

1.)

Is it possible to use the artificial horizont animation source on something else than class air? Does it work on the ground anyway?

2.)

Using four points from trunnion model or inside memory lod. I.e. one front,back,left and right each same distance from center, named gyro_front etc... and using selectionPosition to get their elevation ASL? Then using triognometrics its possible to calculate the tilt and bank angles(vectors too?) of the trunnion.

Its just ideas, nothing tested right now because im busy with some other ArmA Stuff atm, like my Javelin (TBA in WIP thread soon) and my M93 Hornet.

[NonWonderDog 0]

Finding the trunnion tilt isn't the problem.  Well, it's a problem, but it's one I've already solved.  Take a look at the "Trigonometry Ahoy!" section in MBTELRF.sqf.  It's several lines of overcomplicated trigonometry that ultimately outputs a unit vector aligned 90 degrees starboard with respect to the turret.  All that's left to find the tilt is to take the arcsine of the z-component of this vector.  (I think I've tested this bit of code, but you might want to check that it actually works.)  There are lots of extraneous calculations here that can be yanked out, too; I wrote this section partially as reference, and I was going to streamline it later.

The problem is programming the corrections into the FCS.  It's probably not as hard as I think it is, but I just can't quite wrap my head around what's needed.  Is trunnion tilt tracked continuously, or is it a snapshot value?  If it's a snapshot, when is it taken?  Trunnion tilt would affect both lead and elevation--does the computer continuously change the superelevation as you scan the turret (lots of stuff might need to be rewritten if it does)?  How does this work in the T-72?  There are maximum correction angles to implement as well, and presumably some kind of notification if you're over the limit.  

I'll look through my documentation and see if I can find any specifics as regards to capabilities.

[PhilippRauch 0]

Some Info for those that might be interested:

The real FCS uses current vectors from their gyro and the turret system will always try to keep the barrel level

(plus minus the wanted elevation for the lased target. Atleast with Leopards Turret and stabilizing system from Rheinmetall. Although the barrelmovement might have some little delay because of mass vs. hydraulic power etc... it all depends on terrain, speed, mass of barrel etc... a little delay might also be included on purpose (not sure about that) to avoid to erratic barrelmovements while in rough terrain and high speeds.)

It is simulated inside Steelbeasts (1) like that and you can see it in videos shooting on the move, its also mentioned in Rheinmetalls own Publications where they point out the high demands for such systems in tanks. Stablizer for shipdeckmounted guns seem to be much easier since they "only" need to compensate some sine style movements.

I also have the T-72 ("Balkans on Fire" or something) sim. But i never got around learning those eastern weaponssystems and i dont remember if they have a stabilizer in T-72s. I bet they use stabilized guns for the T-80s and higher...

If hydraulics or gyro fail you can definetly forget hitting anything on the move except directly infront of the muzzle. Or you are very good at handcranking...

I think it was the same with the Abrams. Those two use the same gunsystem. Both the 105mm and 120mm of the Leopards where developed by Rheinmetall. The 120mm variant has a three-axis stabilizer and is also produced in license in the USA for the Abrams.

Both Tanks where originally (back in 60s-70s) thought to be a joint-development, but many differing ideas and already done construction led to those two quite differing tanks.

AFAIK only the Lasers and the Cannons are the same on both tanks. All electronics are made by national companies.

I just mention the Leo2 because both use the same cannon and same ammunition, so their ArmA FCS can be quite similiar if not the same...

And the trigo ahoy section, nice i learn from it... :P

[NonWonderDog 0]

T-72 is definitely stabilized, but the stabilizer is kind of crap.  The whole system is very different from the Abrams system, and it's actually implemented rather well in Balkans on Fire.  

The big red light at the top of the gunner's sight isn't just there to tell you the gun is loaded in real life.  In real life it's there to tell you that the gun is loaded and aligned with the sight.  The gun stabilizer in the T-72 is pretty damn slow, and the gunsight is not only much faster but it has a much greater range of elevation (in this mod I've set everything to the gun limits).  There are a bunch of little oddities with the system, too, like the turret stabilizer's propensity to overheat if left on too long.  The turret stabilizer is also slow as hell, of course, and the chassis is perfectly capable of turning faster than the turret motor can keep up with.

But again, that's not really the issue.  ArmA takes care of the stabilization issues.  The stabilization is too fast and too perfect, but we don't have any real way to change it.  The issue from our perspective is when and how the fire control computer gets its inputs and changes the superelevation and lead dependent on that data.  

That is to say that the script doesn't have direct control over gun elevation, but only controls superelevation--the elevation of the gun above the sight line.  On flat land this is pretty simple; for a certain range you have to elevate the gun a certain amount to hit the target.  If the tank is tilted, you still have to elevate the gun the same amount, but the elevation is out of plane with the turret and the trunnions.  Furthermore, the relative plane changes orientation as you rotate the turret side to side.  

In an M1A2, the three-axis stabilizer always keeps this in mind and aligns the gun with where it needs to be to hit the target.  You barely even notice that it's happening, since the sights are independently stabilized from the turret in both axes.  You just put the target in the sights, lase, and fire, and you don't know any better as to what the computer's doing.

The M1A1, however... I just don't know.  If it continuously updates due to trunnion tilt, then tracking a close-in target must be a very odd experience when you're on a slope.  The turret and reticle would slew at different rates depending on where the turret is currently pointed, and it seems like that would be very disconcerting.  It could be, although I doubt this, that the tank senses trunnion tilt only once when you lase a target and applies a correction based on that instant no matter how long you track the target.

If the T-72 has trunnion tilt corrections in its FCS (I think it does, but I'm not sure), then this is probably how it works.  It would sense the tilt once, and output corrected info to the gunsight based on that.  I don't think the computer outputs real-time corrections to the gunsight for anything.  I think, though don't hold me to this, that the computer actually changes the reported range depending on trunnion tilt, as the superelevation is inexorably linked to range in the TPD-K1 gunsight.  (There are lots of references in the documentation to "equivalent range" as opposed to "actual range"--it's all very odd.  If I remember correctly, the "actual range" is only reported on an auxiliary display next to the gunsight, while the "equivalent range" is the one shown in the left eyepiece.  The computer automatically scrolls the gunsight elevation to the "equivalent range" when engaged, and that range stays displayed for reference if you manually scroll the range up and down from there.  It's all very primitive but workmanlike, like most Soviet technology.)

[PhilippRauch 0]

M1A1 has the same 120mm M256 smoothbore cannon as the M1A2. Only the variant M1/IPM1 has the 105mm M68A1 rifledbore variant, which is the same as in the old M60 Tank and if im not totally wrong, it must be also the same as in the old Leopard1. EDIT: Seems to be a british cannon model in the M1.

The big difference in M1A1->M1A2 are the sensorsuites, comms, aircon and some other electronics. I couldnt find any references mentioning a different FCS on those two tanks.

When i talk about a "cannon" or "gun" i mean the whole gunsystem, which includes stabilizers etc... so "gun"wise the A1 and A2 variants show no difference. The big difference might be in quicker and more reliable target acquisition due to improved situational awareness of the crew due to those aforementioned upgrades.

So it seems we can (basically) service three different tanks with one FCS (M1A1,M1A2 and Leopard 2) since they use the same armament. And i remember some other foreign tanks with same cannonsystem (apart from licensed Leopard models). And as such can even use the same ammunition.

EDIT: small documentary showing some nice footage

[NonWonderDog 0]

I don't know of the fire control computers are different (I think pretty much every modern western tank uses the same Computing Devices Canada unit), but the M1A2 has a slightly different Gunner's Primary Sight.

The sight in the M1 and M1A1 is the one in this mod; it has a one-axis head mirror where the reticle slews left and right on the glass.  The M1A2 has a two-axis head mirror that keeps the reticle centered at all times.  The Leopard 2 has a similar system.  

I can't find any direct references to this in Janes, but one of the new components in the M1A2 is the Line of Sight/Dual-Axis Head Assembly.  I'm pretty sure that's the new GPS component.

[chappy 0]

M1A1 has the same 120mm M256 smoothbore cannon as the M1A2. Only the variant M1/IPM1 has the 105mm M68A1 rifledbore variant, which is the same as in the old M60 Tank and if im not totally wrong, it must be also the same as in the old Leopard1. EDIT: Seems to be a british cannon model in the M1.

The big difference in M1A1->M1A2 are the sensorsuites, comms, aircon and some other electronics. I couldnt find any references mentioning a different FCS on those two tanks.

When i talk about a "cannon" or "gun" i mean the whole gunsystem, which includes stabilizers etc... so "gun"wise the A1 and A2 variants show no difference. The big difference might be in quicker and more reliable target acquisition due to improved situational awareness of the crew due to those aforementioned upgrades.

So it seems we can (basically) service three different tanks with one FCS (M1A1,M1A2 and Leopard 2) since they use the same armament. And i remember some other foreign tanks with same cannonsystem (apart from licensed Leopard models). And as such can even use the same ammunition.

EDIT: small documentary showing some nice footage

the main difference with the FCS in the m1a2 versus the m1a1 is that the m1a2 has a peri. This means the FCS incorporates TC overrides and slave to peri/slave to gun commands. (much like the leopard 2)

also, just throwing it out there, if u go through and change the M2 included in the ACE mod, the M2a2/3 shouldnt be able to fire TOWs while moving.

the biggest 'to do ' on the list should really be making it MP capable. Even if its limited initially to a couple of the most popular vehicles (t72, m1a1 m1a2) getting it MPable would be a big improvement.

let me know if you want any help at all. Im pretty crappy with coding etc although i could possibly help work on the MP component. more than happy to help test or provide feedback on realism

[max power 21]

also, just throwing it out there, if u go through and change the M2 included in the ACE mod, the M2a2/3 shouldnt be able to fire TOWs while moving.

That's weird.  The helicopter version can fire tow missiles accurately while moving faster than the Vne of the Cobra F model.  Maybe the wires will get caught on stuff.