Clearance of harbor navigation channels with high‐resolution bottom surveys at 10 knots

The safety of navigation channels leading to or within a harbor can be ensured by repeat high‐resolution bottom surveys to detect new hazards or obstacles. This task requires a sonar system capable of acquiring high‐resolution acoustic backscatter imagery and bathymetry. Because of the generally shallow water depths ( 20 m), survey efficiency dictates data collection over wide swaths at high speeds. We have demonstrated these capabilities in October 2006 in New York harbor, NY, with a Klein 5410 multibeam side‐looking sonar system yiedling swath coverage of at least 7 times the water depth at a nominal survey speed of 10 knots. This has been achieved by integrating the hull‐mounted sonar system with precision attitude ( 0.01 deg) and timing ( 10‐6 s) references, and by designing and implementing a full vector processing algorithm to obtain co‐registered high‐resolution bathymetry and acoustic backscatter imagery, allowing us to resolve sub‐meter targets. [Work funded by NOAA‐NMFS].