The Armored Assault Vehicle (Early), or AAV, appeared to have been used by the Ifriit-Naabal during their earlier failed expedition. The vehicle appears in the third mission of Homeworld: Deserts of Kharak exclusively.
This earlier variant of the AAV has a few key differences compared to it's more modern counterpart, the SA2-17 Phalanx. Most notably, the vehicle has a different turret, although the main weapon is presumably still a kinetic gatling cannon.