A complete breadboard four-channel assembly of programmable beam-steering and signal processing has been tested at sea. Preliminary experiments have confirmed successful operation of computer-controlled beam-steering, signal amplitude conditioning, and active and passive processing under conditions representing a fully integrated system. Having demonstrated the viability of such an assembly, work is now progressing on a second version, adequately engineered, to stand the rigours of a comprehensive sea trials programme and operate reliably for long periods of time. As far as the future role of the c.c.d. in compact sonars is concerned, this is open to speculation. The c.c.d. development work summarised in this paper is the result of a six year programme of design, evaluation and improvement aimed at the sonar application. Present designs are considered to be close to the limits of what can be achieved in charge-coupled technology, and it remains to be seen whether equivalent digital devices, with improved stability and dynamic range, will eventually appear as a result of future programmes of work in VHSIC/VLSI technology. In the meantime it is felt that the existing c.c.d.-based system referred to above will continue to provide a very useful research tool in investigating the application of programmable spatial and signal processing to improve the performance of the small-array compact sonar.

Inspec keywords: sonar signal processing; charge-coupled device circuits; VLSI

Other keywords: small-array compact sonar; channel assembly; CCD processors; signal amplitude conditioning; programmable beam-steering; charge-coupled technology; VHSIC-VLSI technology; signal processing; computer-controlled beam-steering; equivalent digital devices

Subjects: Sonar and acoustic radar