Research And Design Of Acoustic Doppler Current Profiler

China has abundant marine resources,and the rational use and development of marine resources will contribute to the development of my country’s economy and the improvement of people’s quality of life.Among them,seawater velocity information is an important element of marine data observation,and also an important parameter to obtain marine resources,which directly serves national defense,production,shipping,transportation,fishery,and port construction.Therefore,the observation and research of ocean currents has become one of the hotspots in the exploration and development of marine resources.At present,the acoustic Doppler current measurement technology is the most popular current measurement technology,which can make up for the defects of poor real-time performance and complex current measurement of domestic current meters.Compared with foreign Doppler current measurement technology,the acoustic Doppler current profiler studied in my country has problems such as poor stability and slow operation speed.Regarding the issue above,this subject researches and designs a new type of acoustic Doppler current profiler.Considering the accuracy of flow rate measurement and real-time signal processing,two technical improvements of FPGA-based hardware circuit design technology and flow velocity signal analysis and processing are proposed.The new FPGA has the advantage of high-speed parallel processing of signals.The function of the Acoustic Doppler Current Profiler hardware circuit is optimized.Finally,the flow velocity data is calculated by Zoom-FFT and coordinate transformation,and the system software is designed.The specific research contents are as follows:Firstly,this thesis briefly introduces the research status of the Acoustic Doppler Current Profiler,the basic principle of Doppler blood flow measurement and the method of Acoustic Doppler Current Profiler layered measurement profile are analyzed in detail.On the basis of relevant theoretical research,the overall design scheme of the system is designed,and the main technical indicators are determined.Secondly,this thesis realizes the data acquisition and signal processing of the Acoustic Doppler Current Profiler current measurement echo signal,and uses the fast Fourier transform to perform spectrum analysis on the flow velocity data to estimate the frequency offset and obtain the current flow velocity,which greatly improves the The performance and design flexibility of the equipment are improved.This paper will introduce the research process of hardware circuit design,software design,flow velocity signal processing and Doppler flow measurement algorithm.The hardware part mainly includes a control module,a transmitter module,a receiver module and a peripheral measurement circuit for related marine parameters.The software platform includes communication protocol design,flow rate data processing and software interface.The flow velocity signal processing based on FPGA related modules is realized,and the Doppler flow measurement algorithm is studied and formulas are derived.Finally,based on the theoretical analysis and algorithm research of flow measurement,the Acoustic Doppler Current Profiler software and hardware platform built in this thesis is assembled and debugged,and laboratory tests and marine comparative experiments are carried out.The test results show that the Acoustic Doppler Current Profiler works stably and reliably,and the accuracy of flow velocity measurement has reached the expected standard.