Raid Fleets don't usually pose a problem if you are smart.
In short: you need infantry and a barracks.
Infantry are sooo valuable. Why? Because they can capture build pads.
Distract the incoming rebel tanks with garrisoned scout troops. During this time, build turrets to counter whatever the rebels are throwing at you. Entrech the stormtroopers, and watch the magic.
TIE maulers are good for countering infantry, and AT-ATs are good for everything (and they spawn stromtroops), but stromtroops and a barracks can repel pretty much anything in a raid fleet by building turrets.
This is not your island. This is our island.