Geoacoustic Echo Processor (GEP) for high resolution mapping and bottom classification

Techniques in multibeam sonar signal processing have been merged with new C40 hardware to provide a system with enhanced resolution, improved processing turnaround, shallow water charting and sediment classification. The system, currently known as the Geoacoustic Echo Processor (GEP), has been successfully tested aboard the Navy´s new T-AGS-60 class survey ship. The prototype has been proposed as an enhancement to the current T-AGS-60 mission in both shallow and deep water surveys. The latest hardware configuration of the GEP consists of a VME PowerPC system hosting eight TMS320C44 digital signal processing (DSP) chips and an Exabyte tape drive for processed and raw data recording. GEP processing can be performed in parallel with the existing shipboard systems or in stand alone mode performing all sonar functions. Bathymetric data are sent over a LAN to display terminals. The GEP builds upon the deep water technology of its predecessor Sonar Array Survey System (SASS), adding special enhancements for split array processing and very shallow operation (30 m). Sonar signal processing is accomplished using a split array technique for deep water and multi-segment array processing for very shallow operation. In multi-segment processing, each half of the array is divided into three overlapped segments, providing multiple estimates of range,