Galactic Senate Hub is a technology that is unique to the Republic, and can be researched at the Fortress in Tech Level 4. It costs 500 Nova and 350 Ore, and gives Fortresses +2 range and Line of Sight. In addition, they gain +2 attack vs Aircraft, Mechs, Heavy Weapons, and Troopers.

"In Tech Level 4, the Republic may bolster its Fortress structures with the Galactic Senate Hub, which gives Fortresses greater range, line of sight, and attack power against Troopers, Mechs, Heavy Weapons and Aircraft."
—Manual description