Ive considered making a topic on this. Getting devs to implement radar and missile reports require more work than doing the report itself. One shouldn’t have to bug all the tech mods and Smin to get anything done. It seems players from all tech trees agree that more priority should be done on missile and radar simulation.
Not only does the AIM-54 have a dedicated dogfight mode, which is a known thing, we have a congressional hearing stating the missile is very capable in dogfights. MAYBE if it wasnt modelled missing a full 32% of its max G pull it might actually do something at closer ranges despite its “slow acceleration”.
I understand this point, it doesnt change the fact that were now dealing with 4th gen IR AAM’s like the R-73 and yet radar missiles are worse at low altitudes than the AIM-7E was 3 years ago, and have become a borderline non-credible threat because theres an easym,ode “I win” way of defeating them by just flying kinda low which has literally no disadvantage besides fuel consumption at this point because of the ungodly contrails that make flying at high alt for ambushes complete suicide.
The AIM-54C’s seeker upgrades are quite literally stated to improve capabilities against targets close together and at low altitude and high EW envorinments. A must when an intended use of the missile is fleet defense vs waves of AShM.
What else explains “An ability to identify targets by individual characteristics through pre-stored computer simulations”
It quite literally describes NCTR
Pretty sure its difficult for a missile which lofts UP to very high altitudes before dropping down on targets from above to get beneath a target to take advantage of this in-game feature…
1 Like
Below 3nm head-on the AIM-54 has worse performance than the AIM-7F… from 3-9 nautical miles it has the same maneuvering performance, and beyond that the AIM-7F drops off and the AIM-54 continues to have improved maneuvering performance against targets until guidance limit.
Likely just incorporates HPRF and MPRF modes like AIM-120.
It could mean something much simpler. Identifies targets based on speed, RCS, or EW techniques and knows what mode to best intercept with… idk.
Doesn’t always need to loft above the target irl, especially at ranges where it will still be burning.
This is about targets close in angle and radial speed, not close in range. I am not sure if AIM-54C seeker is able to track targets in range at all. For example all AIM-7, Skyflash and R-27R - they can’t.
I suspect that AShMs don’'t notch and don’t turn away.
No idea, it is not specified in this short text.
There is actually no need to identify target for the seeker, the seeker only needs to distinguish btw targets and chaff or ground returns.
R-27R seeker for example can reject returns from large ground areas (not from high-reflective small ground objects) by spectrum width and angular noise parameters - this is very far from NCTR.
In the game all SARH and ARH seekers don’t track ground returns, but can’t see through them.
Typical target of AIM-54 is a missile or a bomber. And they seems don’t notch.
Anyway even fiighter radars like AN/APG-68 with their narrower beam width, multiple modes and complex signal processing can be notched, because it the MBC and target return overlap both in range and doppler speed, they just can’t be separated.
1 Like
The dogfight ability of the AIM-54 at this point is quite frankly a horrid joke as well seeing as one of the technical moderators @_David_Bowie posted a whopping 7 secondary sources on the old forums, all claiming the AIM-54 was dogfightable (among other things these sources discuss, such as AIM-54C seeker improvements).
So its not like the info isn’t already very much available, its just being ignored, just as the AN/AXX-1 TCS bug report is being ignored, just as the smokeless motor issue is being ignored, just as the fuel tanks on the F-14B are being ignored.
Its not how they ‘look’, in the frequency domain you just get a return that quicky goes towards the MLC as it slows down. This can be handled by V gates. If you got a beaming and chaffing target, the ability to keep track would depend on the resolution cell, which depends on the radar(beamwidth and range gate), and on the radar power centroid created by the return of the chaff & sideaspect target RCS.
Take for example a beaming plane against the sky. The power centroid is directly on target and RCS is 50m². And lets take that the beamwidth of the radar is such that the cell has a radius of 400m at a certain distance. If the plane starts chaffing, the power centroid will slowly shift to the growing chaff cloud. As the chaff is slowing down and the fighter continues on its speed, the distance between it increases. As the chaff cloud expands, its RCS increases thus it shifts the power centroid towards it. Because the diameter of the radar beam is finite, 800m, and the distance between the chaff and plane increases, the power centroid will be closest to the strongest signal. At some point either the chaff or plane will leave the resolution cell, and it will be the one that is farthest to the power centroid.
Look, no NCTR involved.
But ingame there’s no such thing as power centroid and side aspect RCS…
NCTR is pretty classified, we don’t really know how spectral analysis is done or what they do. We only know one type and its through JEM.
MPRF…
They do… the CW signal from the illuminator has the the frequency modulated. From multiple sources. Awg10( F-4J) CW signal is frequency modulated.
1 Like
AIM-120 has both. AIM-54C - ???
The main advantage of MPRF is all-aspect look-down capability.
Very doubtfull that it is highly desired for missile developed for long-range interception of Anti-Ship missiles and heavy bombers.
Range unambiguity solving can be done for HPRF for furthre range tracking, however, it is really complex and time-consuming. It works for N-019 radar on acquisition-track phase in HPRF mode.
AIM-54A was developed initially for that, AIM-54C specifically required better all-aspect look-down capability and use against more modern, fighter like targets. The AIM-120 seeker was also developed off the basis of the AIM-54C so it is likely.
1 Like
Players dont either when they can LITERALLY just flight straight an somewhat low altitude to have total immunity against all radar missiles ingame.
Majority of claimed AIM-54 kills in real life were fighter targets hit during the Iran-Iraq war and that wasn’t even an AIM-54C, those were AIM-54A’s. Clearly their ability against fighter targets wasn’t exactly lacking
1 Like
Fighter targets who mostly lacked RWR, countermeasures, training, etc.
Oh look, wiki… nice
1 Like
AIM-54C had specific provisions made to the upgrade seeker to improve capability against sea skimming AShM’s, clearly something that may require enhanced look down capabilities. This has been stated over and over.
provide the capability to track through the target’s beam aspect and to guide on targets in a stream raid".
Stream raid are fighter in a line to the f-14. If you fire missiles to them, all phoenixes will home to the first target despite you launching them to individual targets
5 Likes
AN/APG-59 and N-019 can track target in PD mode both in range and speed with HPRF only. Some complex pre-calculations in acquisition phase and tricks are made, but if the target is tracked in range it doesn’t mean that it is gated well in range against ground clutter due the high range ambiguity.
Why even bother at this point?
We pull every single publicly available AIM-54 source there is out there and the answer is just a mix of “i dont think so” “thats not how we want to model it in-game”, “I dont think you understand” etc…
These bug reports are just a massive waste of time. They couldnt even be bothered to give it a smokeless motor after they started giving them to everything else that had one ffs.
1 Like
I understand, the gates are way larger than what MPRF would allow. But in a lookdown situation of a fighter A at 10km altitude tracking a beaming fighter B at 5km altitude at a distance of 40km. Thats ~7° under the nose, for simplicity the background is another 40km behind the plane. There’s gotta be some tracking done if they are range gated. I don’t think the range gate is 80km.
We agree that if the fighter B is lower such that the ground clutter is withing the range gate, track is lost. But a gate must be set
CW or HPRF + FM modulation allows both resolution in range and radial speed so targets flying with the same speed and at different ranges will be separated by such seeker.
It also increases target return - to - MBC ratio due the MBC spot size in range.
But it also increases MBC clutter area in the frequency scale due the MBC spot size in range. For example a tail-on target (with radial speed smaller than the minimal MBC radial speed) at a range larger than the MBC min range appear in the MBC clutter because frequenct = speed + range. Without FM this target will appear in MBC-free region.
There is no obvious advantage of having FM in order to see through the notch.
I have already explained this in the topic about Skyflash missile.
2 Likes
Do we have any sources/data even saying what prf it uses? (The missile’s on board radar) It seems like they went through a lot of trouble developing ECCM techniques for it if it is only effective in tracking head-on targets.
This is a bad example
Hf = 10 km
Ht = 5 km
Dh = 40 km - horizontal
D = 40.3 km - slant
Elevation to the target is atan((5 km - 10 km) / 40 km) = -7 deg
Beam width for AIM-7 seeker is 7 deg * 2 = 14 deg - this is why 7 deg is here
MBC starts in range from 10 km / sin (7 + 14 / 2 deg) = 41.1 km to 10 km / sin(7 - 14 / 2 deg) = infinity
Only 41.1km - 40.3 km = 0.8 km separation between target and MBC in range.
But this is not the worst news.
If HPRF is used that means for example 2 km unambiguous range and range gate 0.2-0.4 km will fit all returns from 2.2-2.4 km, 4.2-4.4 km, e.t.c. The range gate will receive all returns from MBC behind the airplane becase MBC is longer than 2 km.
2 Likes
If HPRF+FM is used that means for example frequency shift for 200 m in range is the same as for to 2 m/s in radial speed.
Let’s assume that fighter speed is 300 m/s.
MBC starts in radial speed from 300 m/s * cos(7 + 14 / 2 deg) = 290 m/s to 300 m/s * cos(7 - 14 / 2 deg) = 300 m/s.
Target radial speed is 300 ms * cos(7 deg) = 298 m/s.
Without FM target radial speed is in MBC area.
Target frequency shift is equals to 298 m/s + 40300 m / (200m / 2 m/s) = 298 m/s + 4030 m/s = 4328 m/s
MBC starts from 290 m/s + 41100 m / (200m / 2 m/s) = 4400 m/s to infinity
They are separated well by 72 m/s - this is wider than normal speed gate width.
Ok
Now assume that the notching target with speed of 300 m/s turns slightly towards to the fighter. The angle changes from 90 deg to 75 deg.
Target radial speed changes from 298 m/s to (300 m/s + 300 m/s * sin(90 - 75 deg)) * cos(7 deg) = 375 m/s.
The frequency shift changes from 4328 m/s to 375 m/s + 40300 m / (200m / 2 m/s) = 4405 m/s. The target now doesn’t notch, but target return appears within the notch area from 4400 m/s to infinity.
Yes, spectrum density of MBC with FM is smaller, but if it was 1000 times stronger than the target return w/o FM and becomes 1000 times better because MBC gets 1000 times wider - it still not strong enough, but MBC is much wider. Doesn’t look a good deal.
2 Likes
I know what you mean, but you are forgetting range in the doppler range map. MBC spot size in F increases but it’s center is on the (large) range gate(s) created where the center of the beam is. As you get farther from it, in the noise is reduced and with enough SNR, a traget can be found.
Look at this map. Range is 0 to N range bins(created by the FM) and doppler from 0 to M Doppler bina
You say spot size increases, I agree. But on the range axis the MLC ia centered in the beam center at range 5th bin. If the target is getting tracked and is beaming, near the ground. The target will be in the 4th range bin, its signal return will be lower than the clutter. Now lets go on my first example. The target is on the 3rd range bin. If the side aspect RCS is big enough and SNR is sufficient track can be kept.
Why is the beamwidth 14 degrees? I’m not getting this or misunderstanding what you want to say here.
Of course if the BW is as large as 14° the area illuminated will offer a larger return bandwidth.
Sin(7-7) is infinity, I don’t get your math or notation. But if I’m understanding what you say, a 14° beam centered at -7° in elevation will look from angle (-14° to 0°[horizon]). If its for example ok.
Of course you get a an integrated look area of infinity. But the signal return is not infinity. There’s a point the noise is bliss. And simply ia ignored due to the SNR.
On the doppler range map MBC at f0 is from the altitude return to infinity. But the intensity is not uniform but centered on the beam. Even if you might argue that the MBC is not on the horizon( which is what I think you want to point out), the sidelobes do and they don’t get infinity return because the intersected area goes to infinity.
Think of which ground return is stronger, that at 40km or the sum from near horizon to some x distance the signal isn’t even picked by the receiver!
When you range gate HPRF, you take into account the range bins created by the FM. Look at the doppler map again, if we use these (FM) range bins, the target(if enough SNR) will pop out between the rangebin(s) the MBC is and 0.
Let me answer the other post later, is 4h30am here
1 Like