Side scan sonar

A study using side scan sonar was carried out to study the morphology of the sea bed in the test bed in detail.

The concept that underpins this apparatus is the emission/reception of acoustic waves at a frequency that is sensitive to the irregularities of the sea bed. Digital acoustic images are generated from the reflected signal that allow the sea bed to be mapped, objects to be detected and submerged structures inspected.

The campaign used a C-MAX, SBL CM2 SIDESCAN SONAR at a frequency of 325 KHz that gives lateral cover of approximately 150 metres, as we can see in the next figure. This is towed by a boat and submerged to between 8 and 12 metres from the sea bed.

The next figure shows the transects sailed and the composition of the gross acoustic signal represented geographically.

A post-process based on analysing the roughness and texture of the gross signal combined with other sources such as video sweep and a detailed map of the bathymetry, has enabled us to draw up an accurate map of the characteristics of the sea bed shown in the next figure.