English: The three-person manned submersible 'Austria Sub' equipped with its AquaMap long-baseline (LBL) acoustic positioning system. The baseline transponders (B) which serve as the reference points for navigation will be deployed on the seafloor, and then location surveyed using a combination of acoustic self-surveying techniques and GPS before underwater operations proceed. During a diver, the submarine transponder with its associated sonar transducer (A) will emit pings that are received by the baseline stations, which then reply. Thus, the distance to each station is determined and the submarine position can be computed with sub-meter accuracy.