Two-dimensional transform processor for sonar beamforming using c.c.d. and s.a.w devices

A 2-dimensional transform technique which can simultaneously process both target Doppler and target bearing information for sonar beamforming applications is reported. The system uses charge-coupled-device (c.c.d.) analogue time compression on each hyprophone element, permitting temporal transformation of the data to be performed in a surface-acoustic-wave (s.a.w.) complex-Fourier-transform processor. Transformed data are selected from successive hydrophone records by Doppler cell, and a second transform, effectively a spatial transform, is performed on each Doppler cell. The resultant target bearing and target Doppler information is displayed as a B-scan.