Ok this is what I found that made this level really really easy. Progress through the game until right after you destroy the first SAM. Now, whoever is on the ground, look at the building next to the SAM and you will see a ladder leading to the roof. That little roof area is going to be your saving grace. What you're going to do is spawn all of the waves of enemies, and run back up to that spot and PRONE. All of the enemies can only come from one direction when you're up there, and it will give the osprey gunner plenty of time to handle anything coming your way, and if anything manages to make it that far, they still have to climb that ladder, and if you grabbed a .50 cal sniper rifle, you can unload on them while they're stuck climbing the ladder. Let the osprey gunner handle EVERYTHING. Here are the enemy spawns.
1) Run up to the set of barrels on the wall on the building to your right (right after first SAM) 1 Juggernaut will spawn
2) Destroy second SAM, and run right back to the spot 3 Juggernauts will spawn
3)Run up to the building that leads into the courtyard and this is important, there are two riot shield Juggernauts with a regular Juggernaut and some guys. GRAB THE RIOT SHIELD FROM THE JUGGERNAUT AND KEEP IT
4) After every intel you grab, you are going to book it back to that spot, because every wave will have an increasing number of Juggernauts. There will be 4, 5, and 6 Juggernauts respectively
5)After grabbing all of the intels, the enemy garage will open, run back. 6 more Juggernauts will spawn
OK. Now, after all of that, when you enter the enemy garage, a few more enemies will spawn along with a fellow Juggernaut. You do not need to run back to that spot, but make sure you have your riot shield still and you will hold out just fine if you lead the Juggernaut to where your teammate can shoot him.
Once all of the enemies are dead, run through the garage, revive your fallen comrade, and end the mission.
I know some will be curious about the path that the enemies will take. From the courtyard, they will run through the building corridor, they will run behind the semi-truck, past the second SAM site, around the corner, and along the wall until they get to the ladder. They will do this every time
It may also be worth mention that every wave of enemies will have at least 1 Juggy, and it takes 3 missiles to kill one.