Research for Frequency-hopping Multi-beam Bathymetry Based on Hydrophone Arrays
|School||South China University of Technology|
|Course||Communication and Information System|
|Keywords||Seafloor topography measurement Multibeam bathymetric The multibeam hopping sounding TOA estimation|
Multibeam bathymetric system is a high efficiency, high precision and high coverage of seafloor topography measurement techniques. It is based in a conventional single beam bathymetric and using underwater other can array beamforming technique, a plurality of different angles of the probe beam can be formed in the underwater, to achieve striped probing. Therefore, the multi-beam bathymetric system is particularly suitable for large area underwater investigations. Multibeam bathymetric wide variety, but sounding principles are all using a single frequency acoustic pulse echo detection technology, based on the magnitude and phase-based sounding two categories is divided into the algorithm. Such traditional multi-beam bathymetric technology by the marine environment, noise, the effect of multipath interference, and can not be accurately estimated time of arrival of the first echo; traditional pulse detection method, there is a range resolution The contradiction between the working range. In order to overcome these problems and further improve underwater multibeam bathymetric accuracy, spread spectrum ranging technology by introducing land based transducer array multibeam hopping sounding system and method, and the The program carried out theoretical studies and experimental simulation. The main work of this paper are: First of underwater multibeam sounding technical analysis, including the basic principles of the multi-beam bathymetric system structure, beamforming, sounding algorithms and data correction techniques. Which focus on traditional multi-beam bathymetric use beamforming technology and bathymetric algorithm. Second, the focus of this thesis elaborated, that is based on the technical principles of the multi-beam hopping sounding transducer array. Terrestrial frequency hopping underwater multibeam bathymetric, combined with DFT broadband beamforming based the STFT echo TOA estimation algorithm, make full use of the frequency and amplitude of the echo signal to carry information to achieve the separation of the multi-channel echo echo arrival time of the beam center point and accurate projections. This paper presents the overall structure and operation mode of the system and the key algorithms, theoretically proves the feasibility and performance advantages of the system. Finally, through the simulation experiment to build a submarine echo model, and the model of the traditional multi-beam bathymetric algorithm and this article multibeam hopping sounding algorithm, the comparative analysis of different parameters on various sounding algorithm. The results show that the multi-beam hopping sounding really be able to overcome the defects of the traditional multi-beam bathymetric accurately estimate the arrival time of the beam pointing hopping echo, to achieve higher accuracy underwater topographic survey.