Swath-sounding sonar techniques that use the phase content of the sonar signal to measure the angle of a wave front returned from a sonar target. When backscattered sound energy is received back at the transducer, the angle the return ray of acoustic energy makes with the transducer is measured. The range is calculated from two-way travel time. The angle is determined by knowing the spacing between elements within the transducer, the phase difference of the incoming wavefront, and the wavelength