Abstract: The system for positioning an underwater device including at least two surface transponders comprising a receiver for receiving radio signals transmitted by a geolocation system; each surface transponder comprising: an estimator for estimating at least one radio pseudo-distance; an attachment to a float; and a communicator for communicating information representative of the radio pseudo-distances; and an underwater acoustic transmitter; the underwater device comprising: a receiver for receiving information representative of the radio pseudo-distances; an acoustic signal receiver; a determinator for determining one or more acoustic pseudo-distances between at least two underwater acoustic transmitters and the underwater device; and a calculator for calculating the position of the device in a terrestrial frame of reference centered on one of the surface transponders.

Abstract: The system (100) for positioning an underwater device (105, 110, 115, 120), comprises: at least two surface transponders (125, 130, 135) comprising a receiver (160) for receiving radio signals transmitted by a geolocation system (200); each surface transponder comprising: a means (180) for estimating at least one radio pseudo-distance; an attachment (185) to a float; and a means (140) for communicating information representative of the radio pseudo-distances; and an underwater acoustic transmitter (140); the underwater device comprising: a means (145) for receiving information representative of the radio pseudo-distances; an acoustic signal receiver (145); a means (150) for determining one or more acoustic pseudo-distances between at least two underwater acoustic transmitters and the underwater device; and a means (155) for calculating the position of the device in a terrestrial frame of reference centered on one of the surface transponders.