I think the SLS is going to be entirely for figuring out how to model IIR not great in terms of range but very potent at short range. Once that’s figured out they can add the extended range version
hmm maybe
hopefully
Its the best possible way I can think of to testing IIR seekers prior to their introduction both on heavier SPAA and on aircraft
How fast would Brimstone 2 be ?
They pretty much explained why they don’t want to add the missile with it’s most advanced mode. Having 16 FnFs would also be too much for them, and obviously Gaijin doesn’t want to experiment with mixes of FnF and SAL modes of the same weapon.
Some nations get stabilization much earlier than others.
Some get radar AA with HE-VT much earlier than others.
Some get 13km target lock IR AGMs much earlier than others.
Some get helicopters with FnF weapons while others do not.
…
Good thing we have asymmetrical balancing in the game so not everything needs to be a copy paste of it’s contemporaries.
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Assuming that the reflector is parabolic; and has a frequency of 94 GHz, and a 180mm diameter
Theta, zero ( degrees ) ~= (70 * 0.00318928)/ 0.18 = 0.2232496/0.18 = 1.2402755556 ~= 1.25 degrees
Thus at 5km to find side length A;
5000 * Sin(1.25)
~ 109.04 meters
It covers ~110 meters (+/- 55m off boresight).
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Wouldnt it be +/-110 meters? as that formula uses the Theta in reference to the normal.
Maybe, the angle that the formula is to the first null.
The issue is the game use Half-Power Beam Width for FoV calculations so may differ, I’d have to go look at my textbook, for this to make sure I’m not missing a step somewhere.
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A bigger issue here is that the diffraction limit is the same as your beamwidth. That angle is the angular radius of the Airy disk. Maybe the mmW seeker logic of an AGM-114L/Brimstone/whatever can work out a resolved target with tighter tolerances than the Rayleigh criterion (that’s equal to that angle), but it’s not going to be by much.
Also it should be tan(1.25) * range, no? If we set “Distance between two vehicles=D” and “Range at which you can resolve the target=R” that would give you a rough estimate for the lock range of:
D/tan(1.24)=R
That’s kind of hard to believe, it would be completely abhorrent for cluttered environments in War Thunder, but I can’t see any leeway regarding that. If I remember correctly the AGM-114L is very often launched without target lock using IOG, at least that would somewhat match with this.
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Spikes are hella mid tbh
Only good aginst spaa and light targets
There are likely further processing steps, like range and angular gating on top of Doppler filters to disambiguate moving targets from background sources, and with an INS on board doesn’t need to immediately transition to tracking a target upon receiving a good return and so has time to perform things like Conical or Rosette Scans to work as a Pseudo-imaging system.
If we swap to the AGM-114L, from the Brimstone.
Should the onboard / networked Longbow radar be included as a contributing sensor, some image matching techniques as outlined in
May be relevant as it could provide a radar snapshot (including Doppler Beam Sharpening)of the scene to permit further target / scene refining (e.g. MTI) steps as detailed.
It should also be noted that the -114L uses a much lower Frequency and so has different parameters
The brimstone on the other hand is modern enough and has a dedicated Salvo mode and so can basically just target sort, on top of automatically adjusting the searched volume of each missile to reduce overlap and then target sort based on range / angle to each major return and position in the salvo to ensure missiles are properly deconflicted.
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That’d allow you to get more resolution if the limiting factor was something like your beam width, I think. The diffraction limit is a far more fundamental problem for imaging systems and cheating your way around it is generally not possible with a single, fixed emitter/receiver. I’ve only played around with that a bit for optical systems, but from everything I’ve seen it should work pretty much the same for radar.
I didn’t consider scene matching, that’d allow it to switch to active guidance way before a good return on the selected target is returned. Interesting, wasn’t aware it could do that.
The 114L operates at 94 GHz too, or am I mistaken about that?
Back to War Thunder, the GRB environment is incredibly cluttered. Can the 114L get mid course updates? Because otherwise only being able to differentiate targets at the very end of its flight path might end up with it just going for wrecks, teammates or enemies more or less at random if there’s enough movement. And with longer ranged shots taking ~30 seconds between launch and impact there’s a lot of room for that.
Not entirely sure what band, best bet would probably be asking @Flame2512 or @Gunjob if they had anything on the Hellfire or otherwise more concrete.
apparently the following exerpt comes from; Aviation Week 9 March 1981
So if we plug 0.00768699 ( 2.99792458 x 10^8 / 39x10^9) [Lamda = c/F] into the prior formula
= (70* 0.00768699) / 0.18 = 2.989385
= 0.5380893 /0.18 ~= 3 degrees
Similarly for 35GHz, results are ~= 3.3 degrees
I do know that the seekers used for both the Hellfire and Brimstone share a design linage from the canceled AGM-124 Wasp. Which itself lent heavily on prior work done on integrating PAVE Mover and realizing the strike component of the system.
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Not really an expert on Hellfire. Brimstone definitely used a 94 GHz seeker. This document claims Hellfire used a 35 GHz seeker:
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That tracks with the claim from Aviation Week, and considering the Hellfire is a Boeing (Sperry) product it makes sense.
That cuts the range at which it can differentiate targets down further then. Doesn’t make too much of a practial difference I suppose.
It does not support mid course updates, right? I couldn’t find anything regarding that with a quick search, and that would probably be mentioned.
That sounds like it’d be a headache for the context of War Thunder, if implemented realistically.
Nothing I’ve seen indicates that it can.
But for a LOAL launch the searched volume is probably biased to align with the predicted axis of travel of the target to provide a better chance of a detection should the target change course or speed after launch
These thing can be abstracted and expanded upon or refactored over time.
Duplicating the PARS’s seeker on a hellfire propulsion section would be enough of a baseline -114L to least get a feel for how balanced it would be, and then build out additional functionality as needed.
And it could further be restricted to either using dual rails (in place of the M299 quad rails) and / or a single set of stations to ensure quantities are limited.
Since the Generic smoke grenade could be abstracted to include MMW band obscurants practically nothing would change in terms of counters.
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Then like BOL, “man-in-the-Loop” weapons such as AJ168 and what the rumours suggests IIR is going to be like.
They probably should create a placeholder for full MMW. So its essentially “IR+” better than normal IR guidance, but fully LOBL target tracking without having to mess about with modeling the MMW properly
That would be expected, yeah.
The problem with War Thunder is that there’s a lot of targets stuffed into a very small area, the movement paths are generally the same and within minutes you have them cluttered by the wrecks of dozens of tanks. For a 7 km launch that Hellfire is going to travel just about 30 seconds. If we assume that the tank is stationary and the closest wreck is 30 m away it will be able to differentiate between the wreck and the target at a distance of just about 500 m, ~5 seconds before impact.
War Thunder has a lot of stop and go, tanks don’t really travel with a set speed in a set direction. The chances of the missile acquiring the correct target after it had 25 seconds to move with random speed and direction changes through a field of tank wrecks seems very low (well, unless your target is either camping, moving with continous speed and direction or very isolated).
Spoiler
I plotted the range at which two targets could theoretically be resolved according to the Rayleigh criterion, better than continuing to punch numbers into a calculator. Assumed reflector diameter: 180 mm, just like above)
In cluttered environments IIR F&F weaponry already struggles with switching to wrecks (in War Thunder), and that only really happens if the target gets so close to it they’re pretty much touching. This would presumably be significantly worse.
They could, but that would be extremely unrealistic make believe if what we’re assuming here currently is correct.
At the latest since the addition of the Israeli AH-60 with 16 Spikes I didn’t think the addition of AGM-114Ls would’ve been much of a balancing problem, if everyone were just given VIRSS smoke. A nuisance for other helicopters, no different for ground. Probably would’ve been fine with the full 16 of them.
I never expected the AGM-114L being so harshly kneecapped by the GRB environment if implemented realistically though. Not really sure where to go from there. Implement it realistically but just skip to the JAGM so you can redirect to the intended target using SALH?
Why should that be done, as in “better than normal IR guidance”? From what we’ve seen here it seems to be significantly worse for the context of War Thunder.
Then there should be no issue adding MMW right now then, and we can get AGM-114L and Brimstones
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The Brimstone would still be unbalanced. It’s probably hard to implement if things like scene matching and whatever other special stuff they have were to be implemented, and how exactly it works is probably not known publicly. Scroll up a bit and you’ll find that you can calculate the radius around boresight it scans, that becomes absolutely massive at the lauch ranges you can get out of it.
And then you still have the problem that these things would seemingly target vehicles and wrecks at random in many of the scenarios they’d end up getting used in ingame.