A decade of isophase swath bathymetry

During the late 1980s and 1990s a small company has been having consistently good results with a simple and robust technique for swath bathymetric mapping. Williamson and Associates, Inc. has utilized isophase interferometry on three of its four sonar systems and has made detailed bottom contours in depths to 3300 meters. The physical mechanism behind this technique has been observed for years, but the translation of the physical phenomenon to accurate bathymetric soundings is very involved. It was a unique set of circumstances which allowed Williamson and Associates to make this jump from theory to practice. This paper summarizes how Williamson and Associates' process has evolved to date and how it has been successfully used on surveys throughout the world.