A field of scanner satellites encircled the planet and would report to the stations any suspicious activity or trespassing space vessels they registered. The stations could then launch an attack, either alone (as their firepower equaled some capital ships), or in conjunction with Allegiance-class battlecruisers and other warships, which were tirelessly patrolling the system.
In addition to being part of the orbital defense, the Gauntlet stations also provided headquarters for Human officers to supervise the daily operation of the Byss Security Zone. This included control systems for allowing starships to land on or depart from the surface of Byss.
Though they were heavily armed, these stations also constituted one of the few points of vulnerability in the Security Zone, but it would require a highly-trained force to actually capture one of the stations. An additional factor was the willingness of Palpatine to order a full strike on any compromised station, thus making any hijacking a risky endeavor.