| 摘要 |
This invention relates to a subsea sonar unit comprising an acoustic transducer. The acoustic transducer transmitting an acoustic beam defining an acoustic propagation path for acoustic signals to or from the transducer, and the unit also includes a housing at least a part of which being oil filled and positioned in the propagation path of said beam. The housing is acoustically transparent in the direction of the acoustical beam and has an outer surface with a known shape in said propagation path. The unit also comprising a corrective lens, said corrective lens being mounted in said propagation path between said transducer and said housing part the interface between which defining a first surface having a shape relative to the cross section of said acoustic beam in the propagation path essentially corresponding to the shape of said housing surface relative to said beams cross section at said housing surface in said propagation path. |
