MAV 101:
If you have gone prone, it is much harder for a MAV to kill you.
If they drop it on your head, you can die, but if you are prone on uneven ground, and they can scrape the ground and contact you at the same time; it's a kill.
If you have something solid behind you, like, a wall; you are almost impossible to MAV kill.
The MAV must be at full speed in any direction, and hit you with enough force to move your character, so having a wall behind you will make that difficult.
I am up the crane on Gulf Of Oman a lot, and when I get MAV's coming at me, I put the advertising hoarding behind me, or the main shaft of the crane. It's easier to shoot it out of the sky than it is for them to kill me.
You can easily take out a MAV using your own MAV, by locking on with the crosshairs, and pressing fire as soon as you have the lock.
You can kill MAV's with a Stinger launcher.
You can kill MAV's with an Igla launcher.
You can kill MAV's with a Javelin.
You can lock onto MAV's with any lock on weapon, such as the heat seekers in the jet, or attack heli's, or the guided missile in the tank.
They will kill them too.
You can kill MAV's with any gun, but USAS worx best.
The best advice if confronted by a MAV which is obviously trying to kill you; and you have no cover/USAS:
Move.
Once you try to shoot it down with your pea shooter/other gun that's not a USAS; the owner of said MAV will relish this fact, and spend the rest of your life trying to kill you, until he has.
The other alternative method, is to work out where the owner/sniper is stood still, holding his arms out like Ironman just before he takes a dump, and shoot him till he is dead.
You can use any gun for this, as he will be defenceless and intent on crimping off that length.
But the USAS worx best.

👍
VEXD does not have a USAS.