Underwater vehicle positioning with correlation sonar

Deals with accurate positioning of an underwater vehicle with respect to the sea bottom. The principle uses the spatial correlation of bottom reverberation signals between successive sonar pulses to measure array displacement, as in correlation log. The horizontal translation is estimated from ping to ping and combined with heading sensor information to reconstruct the complete trajectory. This reconstructed trajectory has been compared with a reference positioning system. Experimental results prove that this method enables an accurate estimation of the underwater vehicle displacements. The standard deviation between the estimated displacement and the reference one (for frequencies around 25 kHz) ranges from 1 mm (static) to 5 mm (dynamic)