Question about fox1 guidance

Hello,
So my question is quite simple : why and how a fox1 is able to hit his target even if the aircraft loose the lock few seconds before impact.
For me, as soon as the lock is broken, the missile is not guided anymore, and so will miss his target. But I saw severals times it’s not the true.
I also saw from a youtube video, that in some case, if the radar antenna loose the aircraft because of chaffs, the missile is able to keep tracking the aircraft (it was in a look up situation with a Mirage4000 and a 530D).

For the second part, some planes have a good radar that will look like they locked onto chaff, but is actually still tracking the target. Good example is the f4s.

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1 reason is. Some missils will continue there journey in there current heading and will detonate due to proximity fuse

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Yep and the solution is to change direction when your RWR tells you that your not being locked anymore

If you are not all ready changing direction, would not want to turn into said missile

You change direction from were you where going once your RWR turns off

This statement might be misleading. What happens is that even though the RADAR has locked comething else, the missile (assuming it has a CW seeker head) is doing it’s own guidance. All it’s looking for is a target that illuminated by the RADAR beam that fits the parameters of the original target it was locked on to. CW seeker heads have something called a speed gate. This means it’s looking for something that was closing with the RADAR source at or close to the same rate as the target plane was originally. Chaff closes much faster than any plane, since it’s unmoving in the air, so is easily filtered out. So even if the RADAR locks chaff (Or another plane with a wildly different closure rate), the missile will ignore it and stick to the original target, assuming they’re still in the RADAR beam.

Note that pulse seeker head missile (AIM-9C, 7D, R3R, most early RADAR missiles and some mid French ones) do not have a speed gate, they simply track the largest RADAR return. This makes them very easily spoofed by chaff, which is why chaff can defeat these missiles so reliable regardless of what the RADAR is actually locking at.

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