An Interferometric Bathymetry System is a type of swath sonar technology used to measure water depth and map the seafloor. Unlike traditional single-beam or multibeam echosounders, it uses phase-difference measurements between multiple vertically spaced receivers to calculate the angle of arrival of the reflected acoustic signal. This enables the system to generate bathymetric maps and often side-scan imagery simultaneously. Interferometric systems provide wide swath coverage (often >200°), making them efficient for shallow-water surveys compared to multibeam systems.

Side scan sonar uses fan-shaped acoustic pulses emitted from a towfish to create detailed images of the seafloor. These acoustic “pictures” (sonographs) are similar to aerial photography but use sound instead of light. SSS systems like the Klein 3900 and 4900 are lightweight and ideal for shallow-water surveys or search-and-recovery missions.