Abstract: A sonar antenna with transducers symmetrically distributed along an axis (fore/aft axis) and a perpendicular axis (starboard/port axis) in a plane on a circular base. Placement and polarities of the transducers, along with a phase and sequence of feeding two distinct frequencies to the transducers create four emission lobes inclined at 30 degrees one emission lobe with respect to each axis. Summation of reception signals (echos) from selected transducers based on frequency and accounting for time allow for the determination of fore/aft and starboard/port reception signals from which a velocity of the antenna or a vehicle attached to the antenna can be calculated.