A modern PC-based sidescan sonar acquisition and display system

As part of a University of Rhode Island Ocean Technology program promoting university/industry cooperation, graduate students in ocean engineering undertook the preliminary design and implementation of an inexpensive data collection and real-time mosaicing system for use with dual frequency side-scan sonar tow fish. Objectives for the design included replacing high-cost deck units and mini-computer acquisition systems with a receiver integrated into a personal computer using a single printed circuit board with an external high voltage power supply box. Hardware features on the new system are described. Software features include: (1) real-time scrolling of side-scan data, (2) display of navigation and control data (3) real-time bottom detect and mosaicing of data, and (4) data logging. The hardware system used for initial development consists of a 33 MHz 386 PC/AT bus computer, a SVGA display card and monitor with resolution up to 1024×768×256 colors, and a SCSI disk and tape. A 16-bit AT prototype board contains all the necessary digital and analog components for data acquisition. An external 750 volt power supply provides system compatibility with EG&G and Klein tow fish. Digitized sonar returns are acquired via 4096 byte FIFO data buffers and Direct Memory Access (DMA) for data rates of 40 kilobytes per second. Standard I/O port addressing is used for input from control knobs and communications to the board. A preliminary bottom detect and mosaicing system for display has been prototyped using software in the PC and a Spectrum TMS320C30 DSP card in the 386 computer