Research On Key Technology Of Marine Acoustic Detection System

With the constant exploring and cognition of oceans,its resources and military value have been paid more and more attention.China is a maritime power,and due to the constraints of land resources and environment,it will become a significent task to develop the economy and military value of oceans in twenty-first Century.Therefore,as one of the most important equipments to explore the ocean,the marine acoustic detection system will play an irreplaceable role.This paper depends on State Key Lab of Precision Measuring Technology and Instruments,Tianjin University,and it is supported by Innovation and Demonstration Project of National Marine Economic Region "Industrialization of marine acoustic detection equipment" and Tianjin Science and Technology Project "Development of high resolution marine engineering seismic exploration system".This paper contains years of research on the marine acoustic detection system and the characteristics of the seismic signal acquisition and transmission.According to different conditions of application,the proposed marine acoustic detection system can be used in different fields.The main contents of this paper include the following five aspects:1.In this paper,the topology structure of traditional marine acoustic detection system is optimized.Synchronous control module of odd and even channels is designed based on FPGA.High precision phase locked loop for multi-channel signal synchronous acquisition is constructed.The synchronous acquisition with variable sampling rates and multi-parameter self-check functions are achieved.2.Transmission node of marine acoustic detection system is improved,and its special transmission protocol is developed.In this study,a new method of rapid address assignment is proposed,which is related to the long distance transmission technology of mass data.The performance of remote data transmission and fast address assignment of the transmission nodes are verified by related experiments.3.According to the defects of traditional marine acoustic detection system in the synchronization accuracy,this paper presents a fast synchronization method based on variable sampling rates,and the synchronization error caused by different hydrophone distribution is calibrated by a compensation algorithm of synchronization acquisition.The feasibility of the proposed methods is proved by related experiments.4.This paper also introduces a high-SINR robust adaptive beamforming algorithm based on novel diagonal loading,which changes the loading form of the traditional diagonal loading matrix.The corresponding constrained optimization problem is constructed,and the SINR of the algorithm is improved under signal model mismatch.5.The detailed cable manufacturing process of marine acoustic detection system is explained in this paper,and water tightness test of electronic cabin,hardware circuits performance verification,system debugging and lake experiments are tested.Finally,the reliability and stability of the proposed marine acoustic detection system are verified.