Tnx for the clarification all and excuse my poor English I meant "through"
You have the rulebook quated right.
You can move through enemy system that has just GF,PDS or SD there, but no enemy ships.
Fighters block movement just with Advanced Fighters Technology.
There was some debate within our group how to play this but I figured it was meant like this.
It's worth pointing out, also, that moving THROUGH a system with PDS in it does not trigger PDS fire. Unless the PDS can shoot into the destination (activated) hex, it cannot shoot at the ships.
Did not know that, tnx for pointing that out!