Parametric Array Doppler Sonar (PADS)

A doppler sonar technique capable of measuring ground speed and distance travelled at extreme ocean depths is described. The technique uses non-linear acoustic effects to create the narrow beams required. Performance estimates are calculated and parameters for a test system chosen. Sonar-Pond test results of transmitter beam patterns and source levels are given. The sea trials conducted in July and August of 1975, aboard the R.V. SPERRY STAR off New Providence Island, are described. Evaluation of data taken in water depths to 11,000 feet is made and substantial agreement with original estimates is demonstrated. The feasibility of an accurate, all ocean capability, dead reckoning navigator is thus confirmed.