Design And Implement Of Submerged Buoy System Based On Cilia-NEMS Vector Hydrophone

With the development of marine resources, the marine environment monitoring has beengrowing increasingly. Submerged buoy system, with its long, uninterrupted and wide range ofauto-monitoring water environment has been widely used. The measurement of theunderwater acoustic filed in submerged buoy system often use large aperture scalarhydrophone array to measure the sound pressure. But in low frequency and very lowfrequency measurement of acoustic field, the increasing array aperture has limited theapplication of system while improving system’s performance. The cilia-NEMS vectorhydrophone is a new type of underwater acoustic sensor with small size, low cost, highsensitivity. Therefore the study of submerged buoy system based on NEMS vectorhydrophone is of great significance to solve the array aperture’s issue.The system studied in paper is a kind of small shallow submerged buoy, the system isbased on4-component vector array for underwater acoustic signal detection The submergedbuoy system has eight analog channels and one digital channel, it can record the sensors’signal and the main body’s attitude information, the largest data storage capacity is40GBytes,the data sampling rate of the analog channels is10Ksps. The submerged buoy system candetect underwater acoustic signal in the range of20~2KHz. The main results of the thesis arefollows:(1)This paper finishes the design of submerged buoy’s hardware platform. According tothe signal of NEMS vector hydrophone, we design a low-noise signal processing circuit andanalyze the circuit noise’s factor and corresponding calculation. This paper in systemexpatiates the ADC devices’ characteristics, we use the8-channel,16-bit design of highprecision ADC to design the analog to digital conversion’s circuit. We design a kind of serialcommunication circuit with high reliability. The system power management circuit has avariety of power supplies with seamless handoff scheme which enhances the system’senvironmental adaptability.(2) According to the application requirements, this paper studies the design of key logicwith FPGA as the control core. We research the ADC sampling timing and FIFO buffer’s software design and provide specific application schemes. We eliminate the signal’s jitter bysampling judgment method, improve system’s reliability. This paper describes the internalstructure of Flash chips, studies the Flash chip’s design, analyses a variety of programmethod.The prototype of the submerged buoy system has been going on a number of indoordebugs and outdoor tests. After the preliminary treatment of the trial data, the results verifythe feasibility of the submerged buoy system. The results also show that the submerged buoybased on NEMS vector hydrophone arrays has a good application prospect in themeasurement of the underwater acoustic filed.