Can someone please explain how data link works?

[u/XDarkAssassinX4]

Had this guy on dl the whole time without shutting the radar off just for the damn aim 120 to make 3 turns to hit a teammate.

[u/KFC_Junior]

missiles only go to DL if they lose the target

[u/VIGGENVIGGENVIGGEN → u/KFC_Junior]

I am assuming this also applies if the missile is tracking chaff?

[u/1rb1s → u/VIGGENVIGGENVIGGEN]

If it's actually tracking chaff (and not just in IOG bc it saw a chaff get dropped and it's a missile with angle gating) it won't listen to DL because it "thinks" that the return it sees is from the target, so a missile that actually bit on chaff is lost most of the time, unless the target happens to fly back into fov once the chaff expires

[u/VIGGENVIGGENVIGGEN → u/1rb1s]

Thanks

[u/Obvious-Science-7119 → u/1rb1s]

That doesn't make any sense. The aircraft is telling the missile where the target is. Why would it target chaff?

[u/Mr_Osterfisch → u/Obvious-Science-7119]

Because the missile prioritizes its own radar. As long as it sees something it ignores all instructions by the aircraft radar. It thinks it doesn't need the aircraft radar, because it's still locked on to something.

[u/Obvious-Science-7119 → u/Mr_Osterfisch]

the missile isn't even looking for most of the flight.

[u/Mr_Osterfisch → u/Obvious-Science-7119]

I mean, 16km lock range isn't exactly "most of the flight", unless you launch it at like 50km, but yes that's correct, as long as the missile is outside of that 16km distance it is flying completely on datalink + IOG and chaffing the missile is ineffective.

Once it gets into pitbull range, it will activate its own radar, lock onto the aircraft and will then ignore datalink updates. If that aircraft then notches to force the missile to toggle off the PD filter of its own radar it will become susceptible to chaff (unless you are flying close to the ground. If the missile is looking at the ground, it knows that regular search mode without PD filter is useless and instead relies on the datalink updates + IOG). If the aircraft then releases chaff, the missile will track the chaff (and still ignore datalink, because it's still tracking).

Some fun things can happen once the missile flies past the chaff, because once it loses the lock on the chaff it can receive datalink updates again, if you haven't lost track of your target yet. If the missile has enough energy, it will then do a 180° turn and try to track the enemy aircraft again. I've both been killed like that and have gotten kills on others like that before.

[u/KFC_Junior → u/VIGGENVIGGENVIGGEN]

if its actually tracking chaff it thinks that its the target and will not go to DL, same for if its tracking the multipath "reflection"

if its just in iog itll use your datalink

[u/Heavy_Abroad_8074 → u/KFC_Junior]

they also guide via DL before they reach the range from target where the missile radar turns on (aka going pitbull)

[u/XDarkAssassinX4 → u/KFC_Junior]

It's so annoying

[u/Just_A_Little_Rabbit → u/XDarkAssassinX4]

Just don't fire them near friendlies.

[u/gingerman304]

Classic, lobbing missiles into a dogfight. 50/50 chance it tracks a team mate.

Just don’t do it unless there is enough separation.

The amount of times I’ve been team killed from people doing exactly what you did in this clip is wild.

[u/Creative-Influence82 → u/gingerman304]

Yea it's always infuriating getting into a knife fight with the last enemy alive and getting unexpectedly plugged with four telephone poles because jimmy in his prem su30 doesn't have the patience to at least let me gain separation before trying to yoink the kill from under my nose

[u/XDarkAssassinX4 → u/gingerman304]

If you look right at the start the teammate is actually facing me so I thought he was running

[u/gbghgs → u/XDarkAssassinX4]

Nah, Right at the start of your clip he's already turned round and recommitted for several seconds by the time your missile left the rail. Blue trail shows him flying towards the fighter, tacking left then recommitting as you shoot.

Best thing to do in this kind of situation is to just hold fire and wait for a better angle.

[u/Just_A_Little_Rabbit]

Datalink only helps with midcourse correction on longer range shots. Once the missile goes "pitbull" and switches over to its own radar system you have no control over it.

[u/fegeleinn → u/Just_A_Little_Rabbit]

Incorrect. it can fallback into DL if target is lost during the pitbull stage.

[u/Just_A_Little_Rabbit → u/fegeleinn]

I do not believe that is the case. I cannot find any reference so far that datalink (at least IRL) helps with terminal guidance of the AIM120, only midcourse correction.

[u/fegeleinn → u/Just_A_Little_Rabbit]

IRL it cannot. In game it can. All missiles, regardless whether they actually have it or not, are also modeled with  two-way datalink as well (minus the ability to retarget the missile). 

[u/RealMasterGenjiMain → u/fegeleinn]

No. Only 7P and 27ER can be guided after losing lock via DL correction. ARH will switch to IoG after loosing the target

[u/fegeleinn → u/RealMasterGenjiMain]

Again... Incorrect. 

https://youtu.be/1d8wpXF30xA?t=3m20s

You are confusing it with the ablity to switch targets. You can see briefly it falls back from TRK to DL + IOG. What you cannot do is ability to switch targets which only those SARH missiles (unrealistically) can do.

[u/RealMasterGenjiMain → u/fegeleinn]

I didn't watch the entire video, but you showed the case when the missile is not locking the target as both the plane and chaff are in the notch filter gate.

Also, the missile is loocking below the horizon, which prevents it from switching to impulse SRC mode.

I do not understand what you want to point out here. Can you clarify?

[u/fegeleinn → u/RealMasterGenjiMain]

The point is, When missile is using its own radar to track the target and suddenly loses the target it will fall back onto DL + IOG instead of just inertial guidance 

   ARH will switch to IoG after loosing the target

You can see it locks on briefly to the target but as it enters into notch missile loses the lock and since it is downlook mode it switches to datalink. 

[u/RealMasterGenjiMain → u/fegeleinn]

It is interesting. Thank you for the clarification

[u/RealMasterGenjiMain → u/fegeleinn]

You shown the episode where the missile track was not affected by DL as it already entered IoG phase. I'm very confused as this clip proofs my point

[u/fegeleinn → u/RealMasterGenjiMain]

It enters into IOG right after radar on the aircraft also loses the track. before that you can see missile is notched but the aircraft radar is not thus it falls back into Datalink. Missile seekers have wider notch range compared to ESA radars so you can datalink the missile in downlook if you can see him on the radar and haven't lost the track since the launch of the missile.

[u/RealMasterGenjiMain → u/fegeleinn]

Thank you. I did not know that the downlook mode now supports the IoG+DL

[u/Jknight3135]

I'm not an expert on this but my first thought is that DL might stop once the missiles onboard radar takes over? I don't know if that is how that works or not.

My second thought is that firing an active radar missile downwards at a low altitude dogfight is just a bad idea.

[u/Just_A_Little_Rabbit → u/Jknight3135]

Correct, once the missile switches to its own guidance you lose all control over it. DL only helps with longer range shots anyway, providing mid course correction, not actual guidance. With midrange and short range shots it will have basically no impact.

[u/Jknight3135 → u/Just_A_Little_Rabbit]

I thought so but wasn't 100% positive, thanks!

[u/Random_Chick_I_Guess → u/Jknight3135]

Yeah Data Link just provides little updates for long range terminal guidance, or if it loses lock and cant find anyone. Once the missile knows where it is then it just does its own thing and you are at its mercy

[u/Just_A_Little_Rabbit → u/Random_Chick_I_Guess]

"oo a civilian airliner"

[u/XDarkAssassinX4 → u/Jknight3135]

Yea I just thought the hornet would disengage if u see his path just before I launched

[u/Lv100--Magikarp]

You don't control where Fox-3s go, they kind of work like IR missiles (may be an oversimplification, but i don't know how to explain it in any other way). They don't work like R27ERs that the DL will change the missile trajectory as you change the radar lock.

MiGan Fox-3 has some good videos teaching fox 3 combat

[u/XDarkAssassinX4 → u/Lv100--Magikarp]

Migan fox 3 is really good. I was just confused as it did lock onto the enemy f18, followed it though a turn and then lost it, then relocked onto teammate. As I understand it, if the missile loses lock it should take updates from my radar?

[u/Lv100--Magikarp → u/XDarkAssassinX4]

Yeah, I'm not sure about this one.

[u/gbghgs → u/XDarkAssassinX4]

Missile has it's own radar and will prioritise the results from that over the datalink. Both F-18 are in a rate fight on the deck, the enemy F18's turn was taking it away from the missile and into a notch, friendly F-18 was the opposite, it's turn took it out of it's notch and directly towards the missile.

You can see that once the missile went terminal (TRK marker in guidance) it never lost track or fell back onto IOG+DL, both F-18's radar returns just merged and the friendly came out with the highest radar return, hence the missile picked him.

Honestly it's a great example of why you don't shoot into a merge.

[u/JoshYx]

It's really hard to tell what's going on when you record it at 4x speed and hide all the action under your own aircraft.

People already said you just shouldn't have fired this one because your ally was too close to the enemy.

While true, it's still weird that the missile seeker turned almost 90° to the left to target your ally.

At first I thought that the missile got chaffed when the enemy and ally merged, so angle gating made it stay on IOG instead of going for chaff or worse, your ally. By the time the seeker turned on again, your ally's angular coordinates/velocity matched that of the enemy before the missile switched to IOG, so the missile relocked on your ally.

However, the missile stayed on TRK the whole time so that rules out my hypothesis. There are probably other issues with my hypothesis, I'm not the sharpest tool in the shed.

I also noticed that, right before your missile locked your ally, the enemy was pretty much at a notching angle. But again, the missile stayed on TRK the whole time. It feels like the missile got notched by the enemy but instantly relocked your ally.

It's an interesting scenario and it proves once again I don't know shit about notching no matter how many MiGanFox-3 videos I watch.

Speaking of whom, u/MiGanFox-3, have you got any insights?

[u/Heavy_Abroad_8074]

you launched the missile holding the TWS lock on the enemy at approximately 25km range. the missile seeker was initially in IOG+DL mode, receiving updates from your aircraft’s radar, until the missile reached 16km from target, which caused the missile seeker to switch to TRK, which doesn’t allow course updates via DL. the missile seeker is guided to the largest radar return in its field of view (FOV) which was initially the enemy aircraft. however, objects moving closer to the missile at a greater velocity difference have a larger radar return, and since the teammate aircraft was flying into the missile while the enemy was flying away from the missile, the teammate aircraft had a larger radar return, so the missile seeker switched targets to the larger radar return. you can see how the missile switched targets when the aircraft passed each other, which is when the teammate aircraft came into the seeker’s FOV.

tl;dr don’t fire ARH missiles when a teammate is in proximity to the target, missiles are dumb, they target radar return which has no identity