Defense is one of those things I usually make on the fly, however I found myself constantly making the exact same blueprints on the fly, all the time.
This book contains some outpost defense setups, as well as a perimeter wall system designed for artillery trains.
The wall system was designed to be modular, and upgradable. The blueprints come in three levels, each adding a bit more defense as well as additional laser turrets. Each wall level includes a T Junction, for entering the wall rails, a straight piece, inner and outer corners, an artillery stop as well as a roundabout.
This blueprint was designed as a part of my 'Kitch's Blueprint Book' series on YouTube.