Abstract: The invention concerns the resolution of directional information in sonar arrays. In particular it concerns a method for resolving such directional information, which may be useful in hydrographic surveys. The method comprises the steps of receiving a block of sensor data, containing time series from an array of hydrophone sensors, and beamforming to produce beam data including estimates of the directions of arrival from those beams and estimates of source strength. The method further comprises the steps of selecting a subset of the beams and refining the estimates of the directions of arrival from those beams, and, combining the refined estimates of directions of arrival from those beams with either the sensor data or the beam data, and performing a fit to the sensor data or beam data to develop an output containing refined direction of arrival data and refined source strength data.

Abstract: This invention concerns a sonar antenna. The sonar antenna comprises an axially symmetric acoustic surface having the cross-sectional form of a generally U-shaped curve of non constant curvature. The curve is shaped to allow continuous coherent ensonification such that the power in the echo returned from a uniform flat sea floor is substantially constant. This equipment is used for underwater echo sounding and uses hydro acoustic transducers to ensonify the water and receive echoes.

Abstract: The invention concerns the resolution of directional information in sonar arrays. In particular it concerns a method for resolving such directional information, which may be useful in hydrographic surveys. The method comprises the steps of receiving a block of sensor data, containing time series from an array of hydrophone sensors, and beamforming to produce beam data including estimates of the directions of arrival from those beams and estimates of source strength. The method further comprises the steps of selecting a subset of the beams and refining the estimates of the directions of arrival from those beams, and, combining the refined estimates of directions of arrival from those beams with either the sensor data or the beam data, and performing a fit to the sensor data or beam data to develop an output containing refined direction of arrival data and refined source strength data.