Wide swath bathymetric sonar error modeling for a hydrographic survey ship

Paramount in the design and specification of a wide swath bathymetric sonar system is an understanding of the sources and magnitudes of error which affect system performance. Error contributions from the measurement of sound velocity (both surface and layer depth), roll, pitch, heading, tide and heave, and contributions from hydrophone miss-alignment, were evaluated for a generic system operating at depths of 10-1000 meters. Simulations were performed using a typical sound speed profile to determine the amount of surface and layer depth sound speed error required to produce a 1% depth error or 3.75 meter position error in accordance with International Hydrographic Organization (IHO) SP-44 survey standards. Error tolerances for hydrophone alignment were determined with a bottom model using a 144 element receiver array at varying look angles operating at frequencies of 12 kHz and 75 kHz. After determining the individual error tolerances in each area, a composite estimate of system performance was computed based on equipment specifications for 100 meter and 1000 meter operation with the final result compared to IHO standards