This technology is a novel estimation algorithm that uses acoustic signals with a direction-of-arrival technique for underwater localization. It allows for the infrastructure-less 3D self-localization of multiple autonomous underwater vehicles (AUVs) with no reliance on GPS or global clock synchronization. The technology allows AUVs to leverage simple coded beacon signals to self-localize. Thus, self-positioning and automated neighbor discovery of peers in multi-vehicle missions will support position-aware geographic data routing, directional communication links, swarming, collaborative sensing, coordinated sampling and vehicle navigation. This has been validated through simulation in statistically modeled underwater acoustic communication channels and water-tank experimentation, which resulted in significantly superior positioning accuracy compared with state-of-the-art estimation techniques.