Tank AI, 2d rigidbody projectile trajectory prediction

Hello,

I'm making a 2d tank game and I'm struggling with AI.

The AI tank needs to adjust its barrel angle so that it hits the player(wich has the abbility to move). I have tried various things, but none of them worked correctly.

The problem is that the playground isn't a flat surface, so a calculation like

barrelAngle = distance / 0.18f; wouldn't work

(0,18 is the barrel angle i got after testing various distances and the barrel angle it had when it hit the target)

[EDIT] What I want to achieve is basically predict the path the projectile (rigidbody2d) will follow, and if it's landing point is the player, then execute a method called Fire.

Can anybody help me with this?

Best regards,

Marcel