Design And Implementation Of The Hardware Platform In Imaging Sonar System

With the rapid development of marine mining and marine military defence, the demand forhigh resolution imaging sonar is more and more urgent. Based on this application background, thisdissertation is dedicated to the design and implementation of the hardware platform of a multi-beamimaging sonar.The main researches of this dissertation are as follows:1. The architecture design of the hardware platform including interfaces and modules ispresented in the dissertation based on the architectural principles. The hardware platform isdecomposed into several separate modules including transimitter module, frontend signalconditioning and acquisition module, digital signal processing module and power supply module,etc. The standardized interfaces between modules are also given in the dissertation.2. Based on the top-down approach, the hardware platform including frontend signalconditioning and acquisition module, digital signal processing module and power supply moduleis designed and implemented from the top-level architecture to the bottom-level circuit. Frontendsignal conditioning and acquisition module of180channels mainly deals with the signalamplification, filtering and acquisition functions. Digital signal processing module uses highspeed FPGA as core processors, cooperating with peripheral circuits to implement digital IQdemodulation, decimation filtering and beamforming, meanwhile to control the data transmissionfrom underwater device to principal computer, further more to control the process of realtimeimaging.3. In the dissertation6pieces of8-layer high-density printed circuit board with analog anddigital circuits on board, a16-layer high-speed processor-based board and a pair of system’spower supply boards are designed and implemented. The subjects specifically include the boardarchitecture design, the component placement design, the layered structure design and the layoutconstraint rule design. The final design drawing of the printed circuit board is also given in thedissertation.4. The system principle prototype is verified by lake trial, and the lake trail data shows that, allparameters of the designed hardware platform reach the set standard with large design margins,among which the frontend signal conditioning and acquisition module meets the functionalrequirement, can acquire high-quality echo signal of underwater targets, and the digital signalprocessing module is proved to support operation of various complex algorithms in the software platform, and support realtime communication with principal computer using Gigabit Ethernet.The lake trail also verifies that, designed power system meets the demand of transmitter andreceiver for power, features low level of ripple and noise, and satisfies the design requirements.The results demonstrates that the hardware platform of the multi-beam imaging sonar system inthe dissertation has rational design and excellent performance.