Bistatic sonar,which inherits the merits of active and passive monostatic sonars to some extent,has the advantage of extending detectable area.But it can't obtain the desirable detectable area at all angles,and the detectable area may be inferior to what the equivalent monostatic sonar has at some angle.Based on the energy relationship,the model of detectable region for the bistatic sonar was established,and the relation between the detectable range and the azimuth angle at different baseline length,equival...