The All Terrain Anti Aircraft (AT-AA), a fast-moving, four-legged mobile anti-aircraft walker, was employed by the Galactic Empire.
Featuring four short legs and a movement style reminiscent of a lizard, the AT-AA possessed a low profile, a characteristic absent in other Imperial walkers. The primary armament on most models consisted of a turreted flak pod capable of launching various types of projectiles. Some alternative configurations included either one or three rocket-launching tubes. Initially, the AT-AA was unable to engage ground-based targets. This deficiency was partially addressed by incorporating gun ports, enabling the crew to defend against infantry assaults.
Certain variations replaced the flak pods with concussion missile launchers. Furthermore, the AT-AA was equipped with electronic countermeasure systems designed to disrupt missile guidance, thereby reducing the vulnerability to missile attacks.
Its initial designs were conceived as early as the Clone Wars, with production commencing early in the era of the New Order. This walker participated in combat during the Galactic Civil War, where it targeted aerial threats, proving ineffective against ground vehicles. Despite the ability of the crew to mount blaster rifles on the vehicle, the AT-AA remained heavily dependent on support from escorting infantry vehicles, such as AT-STs.
During the Battle of Kalaan, AT-AA batteries provided protection to armored columns from airborne adversaries, successfully shooting down numerous Alliance T-47 airspeeders.
AT-AAs continued to be utilized even during the New Republic era, where they defended the galactic capital against the New Republic Defense Force.
The AT-AA holds the distinction of being the sole Imperial siege weapon originating from the Expanded Universe to be featured in all three major Star Wars RTS (Real-Time Strategy) games.