Optimization of acoustic profiler characteristics in the scope of underwater archeology and monitoring of underwater engineering objects

Abstract

In order to solve the problem of optimizing the characteristics of acoustic profiler with parametric transmitting array in the scope of underwater archeology and monitoring of underwater engineering objects, the results of theoretical studies of the influence of real conditions on the work of parametric hydro-acoustic systems and of the marine soils and bottom sediments features are presented. The necessary amplification range of the receiving path is estimated to compensate for losses during acoustic wave propagation in water and for the most common types of marine sediments: "coarse sand" and "sandy-silty clay". The necessary acoustic power is justified for the given values of the central pump frequency of the parametric profiler and the difference frequency. The most efficient penetration into the marine sediments which was commonly sand and silt occurred at 10-20 kHz of difference frequency. Penetration of frequencies higher than 20 kHz is not effective due to great power losses. The minimal gain of receiving unit must be at least 40 dB. Design and construction of parametric profiler was suggested. Main units were proposed according to the theoretical investigation. In the whole parametric arrays and hydro-acoustical devices with them occurred very effective in subbottom profiling. Small overall dimensions as was shown in construction allow achieving high resolution. So their application is perspective especially in local underwater archeology using small vessels.