Patent ID: 7173880
Filing Date: 2007-02-06
Classification: B63B,B63C,B63G,B63J,E21B,G01S

Abstract:
1. Arrangement comprising an acoustic array with a sound velocity meter, suitable to be arranged under water, the acoustic array being arranged to suspend in use from a vessel and arranged to receive acoustic signals directly from an underwater device remote from said array and to provide acoustic array output data to a processing arrangement such that said processing arrangement can perform, in real-time, a calculation of a position of said underwater device relative to said acoustic array based on said acoustic array output data, the sound velocity meter being arranged to be located in use at a fixed depth with respect to the vessel and arranged to provide sound velocity meter output data to said processing arrangement, the acoustic array comprising a motion sensor that measures heave, roll and pitch of the acoustic array and provides motion sensor output data to said processing arrangement, said processing arrangement being arranged to correct said calculation of said position of said underwater device based on said sound velocity meter output data as a function of time and based on said motion sensor output data.