Design And Implementation Of Multi-band Low Power ADCP System Based On Embedded Technology

The ocean is an essential part of the earth;however,the exploration of the ocean is still in the initial stage.Since the overexploitation of terrestrial resources,human beings are more aware of the importance of researching and utilizing marine resources.As a result,it is necessary to make accurate measurements of various parameters in the ocean to explore the marine resources adequately.Acoustic Doppler Current Profiler(ADCP)is a significant device to measure marine flow.In recent years,ADCP is developed towards a series of characteristics,such as low power consumption,small size and multi-function.This paper will study the ADCP signal processing platform based on embedded technology.The combination of the embedded technology and ADCP can improve flexibility,reliability,and adjustability of the system.The main contents of this paper can be summarized as follows:1.Study the working principle of ADCP,compared the advantages and disadvantages of three flow measurement methods(narrowband Doppler flow measurement,coherent flow measurement,broadband Doppler flow measurement),mathematically deduced and argued the signal processing process of the broadband flow,and did the simulated analysis about the complex correlation of echo signals,which assisted targetedly with the MATLAB.The results showed that broadband flow measurement is to combine the merits of narrowband Doppler flow measurement and coherent flow measurement.2.Designing the overall architecture of the system,and proposed the multi-core working framework of DSP+FPGA+MCU.Based on this framework,the chip selection and hardware circuit design for each module have been done,including MSP430 and its peripheral circuit design;signal transceiver module design,including FPGA resource evaluation and selection,high-speed ADC selection;data processing module design,including OMAP-L138 loading mode and peripheral circuit design.Completed the construction and debugging of the entire hardware system.Designed a low-power system workflow,In addition,this paper achieved a wake-up method in terms of the low-power consumption system of handshaking mechanism to assist the system smoothly transform from deep sleep state to the working state.The experimental results showed that the system has the advantages of superior data processing capability and ultra-low power consumption.3.Completed the development of OMAP-L138 and MSP430 software based on embedded technology;the designs of the FPGA transmission pulse and the FIR digital filter with parallel processing capability and less resource occupation are completed.The ping-pong buffer method is used to improve data transmission efficiency.To be specific,firstly,this paper improved the traditional self-contained ADCP system and data storage mechanism and proposed abnormal power-down data protection mechanism,which could effectively save and recover data storage timing in the abnormal system condition;secondly,this paper polished the loading method of OMAP-L138 based on OMAP-L138 Dual-core communication mechanism to automatically set up procedure from appointed data storage location;finally,in basis of FPGA reconfigurable technology,this paper designed multi-frequency switch flow function.DSP could achieve on-line update of configuration files through active serial configuration of FPGA.The results showed that this method settled the problems of traditional ADCP that limited with fixed frequency flow measurement and complicated switching frequency condition.4.Developed ADCP dedicated host computer under Windows platform,which solves the cumbersome problem of the traditional ADCP device debugging and maintenance process.At the same time,the echo signal can be viewed in real time.5.The paper did the broad-level test and lake experiment about the main function of the system and assessed and analyzed the results of the test.As a result,the software and hardware functions of the system have been accurately verified.