High-resolution echo-sounding and detection of embedded archaeological objects with nonlinear sub-bottom profilers

Sub-bottom profilers based on nonlinear acoustics offer many advantages especially for detecting and locating embedded objects in shallow waters. They have a narrow beam in spite of small transducers and virtually no side lobes. It is possible to realize mobile low-frequent sub-bottom profilers, which transmit very short sound pulses. Excellent vertical as well as horizontal resolutions at reasonable penetrations are proven benefits of using this technique. In this paper some technical aspects are discussed and a new experimental nonlinear scanning sub-bottom profiler system is described. Results from a field trial in archaeological prospection are shown to illustrate the successful application in practice.