Study And Implementation Of Underwater Acoustic Communication System Based On Differential Time Delay Shift Coding Communication System

Underwater sound communication plays an increasingly important role in the marine field as the current way to achieve long-distance underwater communication.Underwater acoustic communication can not only realize the information transmission of underwater,but also improve the ability to obtain ocean information in practical application.In this paper,a universal underwater acoustic communication system is designed based on the differential time delay shift coding communication system.The required symbol signals are generated by the waveform storage direct reading mode.The communication information is encoded by the symbol type coding and the time delay shift coding,and is decoded through the copy-related technology,so as to effectively suppress the Doppler shift and multipath interference in underwater acoustic communication,enhance the reliability of information transmission and realize the transmission and communication of arbitrary waveform.The main works of the paper was shown as follows:1.In order to achieve differential time delay shift coding communication and establish common underwater acoustic communication platform,the overall scheme of underwater acoustic communication system is proposed.The overall framework and key modules of transmitting system and receiving system are analyzed.2.Focus on differential time delay shift coding communication system,analysis and design the communication system respectively from the differential time delay shift coding,copy-related decoding,data frame format and symbol signal selection.3.The launch system was designed respectively from the hardware and software level.At the hardware level,the Ethernet transmission module is designed based on W5500 to realize the TCP protocol transmission of the data between the host computer and the transmitter.The SRAM is used to design the data storage module.Through the establishment of digital-analog conversion unit and low-pass filter unit,the waveform output module is designed and the logic control module is designed based on FPGA.At the software level,based on the Qt platform to develop human-computer interaction interface,introduce the host computer software data transmission and real-time monitoring functions.4.Designing the receiving system from the hydrophone selection,the signal conditioning module and the signal acquisition module.Using LabVIEW software to develop the signal acquisition interface,and introducing the receiving system host computer software real-time display and storage capabilities.5.The underwater acoustic communication system based on the differential time delay shift coding communication is developed to test the transmission rate of Ethernet.The experiment results show that the data transmission rate between the transmitting system and the host computer meets the requirements of the communication system.The communication system was used to carry out the tank communication experiment.The experiment results verify the accuracy of the system coding information through the time delay shift coding.Finally,using the communication system to experiment with the lake test,the experiment results verify the accuracy of the system under different conditions of encoding and decoding information and the reliability of transmission information.