Research On Target Echo Detection Method Of Microtopography Detection In Reverberant Environment

The existing single beam ultrasound detection device of microtopography in our laboratory can accurately detect microtopography in the clean waters, but the detection device of microtopography has some fatal flaws in a reverberant environment, for example, low precision of detection, the distortion of digital elevation model (DEM) and so on. Based on these problems, under the support of the Planned Science and Technology Project of Hunan Province,"research on sea-floor cobalt crust recognition and thickness measurement method based on the acoustic detection", the author tried to research on detecting method of target echo in reverberation, the main research contents are as follows:(1) The simulation method of deep-sea mining reverberant environment was proposed. The power spectrum density of echo signals were analyzed, according to the power spectrum density, digital filter was designed for echo signal preprocessing.(2) Based on phase space reconstruction theory, the phase spaces of reverberations were reconstructed. The GP algorithm and the small data sets algorithm were analyzed in phase space, the criterion of selection linear region was proposed for small data sets algorithm. According to Simon Haykin’s criterions which are used to judge the signal whether is derived from a chaotic process or not, the results verify the reverberations are chaos.(3) Comparing and analyzing the precision of three methods for solving overdetermined linear equations, pseudo-inverse method was proposed to solve weight vector of the Volterra filter. According to chaos of reverberations, the PIM-Volterra model was built, and simulative signals under the background of chaotic interference was used to test the validity and precision of the PIM-Volterra model, the PIM-Volterra model was used to detect target echo under reverberant interference which from the experiments of microtopography detecting in simulative mining environment, the research results show that PIM-Volterra model is effective to detect the target echo under reverberant interference. (4) Finally, microtopography was detected under reverberation which from simulative mining experiments, the experimental results show that:the target echo detection method of PIM-Volterra model can significantly reduce the effects of reverberation interference in the microtopography detection.