Side Scan Sonar Surveys
Side scan sonar uses acoustic signals (sound waves) to generate an image of the seafloor (riverbed, lakebed, etc.). A side scan sonar is often towed behind a survey vessel but may be affixed directly to the vessel for shallow water applications. The system transmits sound waves toward the seafloor from both sides of the towfish then records intensity of the reflected signal. As the vessel moves along a trackline an acoustic “picture” of a swath of seafloor is generated. Hard areas such as rock or perhaps a shipwreck will produce stronger reflections while softer material such as smooth sand or silt will generate weaker reflections.
Side scan sonar is most often used for sediment type delineation and/or seafloor feature/obstruction detection. Due to the wide swath coverage, side scan sonars are especially well suited for seafloor searches.
OSI maintains a variety of Side scan sonars ranging in frequency from 100 kHz for low resolution wide swath coverage, to 1,600 kHz for very high resolution, high-definition narrow swath scans.