SONAR APPARATUS

PURPOSE:To realize the reduction of the number of elements while keeping resolving power, by separating the elements of the acoustic array of a transmitter-receiver into transmitting and receiving ones to impart special pattern arrangement thereto. CONSTITUTION:A transmitter-receiver stave 1 is a module constituting a transmitter-receiver consisting of transmitting elements 2 and receiving elements 3. An arbitrary element in the transmitter-receiver stave 1 is set to a receiving element and the arbitrary one element or all elements other than the receiving element in said stave are used as transmitting elements. With respect to the acoustic array constituted by the selected elements, equivalent acoustic arrangement becomes a vertical equivalent acoustic array 4 and a horizontal equivalent acoustic array 5 if said acoustic array is limited to a horizontal or vertical direction. By acoustically performing phasing by a receiver and a transmitter, acoustic beam can be synthesized in the arbitrary direction of a space.