apparatus , systems and methods for calculating position of marine seismic acoustic receivers , and for estimating sound velocity profile of a fluid , are disclosed . one position calculation system includes a vessel , two or more vessel hull - mounted transmitters , a plurality of acoustic receivers on a cable being deployed from the vessel into the fluid , and a calculation unit . the calculation unit may be adapted to calculate position of the receivers , and may be used in calculating the sound velocity profile in the fluid and correcting raw seismic data . it is emphasized that this abstract is provided to comply with the rules requiring an abstract , which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure . it is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims . 37 cfr 1 . 72 .