Abstract: A range measurement system for a submarine also having a passive monitoring system with a beam forming circuit, one beam of which may be selected by a signal V.sub.N from a tracking computer. Two assemblies of three hydrophones are located respectively on the port side and on the starboard side of the submarine. The signals supplied by these receivers are correlated with a beam signal S.sub.V of the passive monitoring system selected supplying the delays of these signals. A computer receiving these delay values supplies to the tracking computer the values of the bearing angle .alpha. and the distance D of the noise source.