Design Of Receiving And Acquisition Circuit In Bathymetric Sub-system Of Multibeam Parametric Array Sub-bottom Profiler

The increasing demand for modern marine development promotes the performancerequirement of Sub-bottom Profiler in the field of marine engineering. With the deepening ofthe study for Sub-bottom Profiler based on parametric array technology at home and abroad,the parametric array Sub-bottom Profiler which can overcome the function disadvantage oftraditional LFM Sub-bottom Profiler has became the developing direction of seabed detectionequipment. Based on the National Ministry of Science and Technology supporting item, thedetection system integrating information of multibeam seafloor topography, landform andSub-bottom Profile information based on parametric array, the dissertation makes deepresearch and specific implementation of the receiving and acquisition circuit of multibeamseafloor bathymetric sub-system (abbreviation: bathymetric sub-system), which includes thefollowing aspects:By analysing the related technology of multibeam parametric array sub-bottom profilerand the research situation at home and abroad, then according to the overall project technicalrequirements, demonstrates and promotes the receiving and acquisition circuit of multibeamparametric array sub-bottom profiler’s bathymetry sub-system.According to the receiver design indexs, the paper puts forward the design andimplementation of multichannel receiver, according to each channel of the multichannelreceiver having the same form of circuit, the design of the receiver is divided into themotherboard and single channel receiver module which can receive the signal, amplify, filterand do variable gain control; the band-pass filter type and circuit form are selected bycomparison, and the characteristic is proved by simulation of circuit simulation software;multichannel consistency improving method is researched and used on receiver circuit design;the debugging of multichannel receiver and indicator test are also made.Based on the design proposal of data acquisition circuits, the software and hardwaredesign of data acquisition circuit is realized in the paper, and hardware function moduleincludes a FPGA control circuit, A/D conversion circuit, D/A conversion circuit (generates again control signal) and HOTLink data transmission circuit; the main software work is thecontrol logic design for each function module of the acquisition circuit using Quartus II andModelsim, and for the original digital signal acquired, signal preprocessing operations aremade such as the orthogonal transformation and down sampling; the joint debugging ofsoftware and hardware is done to prove the accuracy and stability. The achievement of the paper participates in the joint debugging of multibeamparametric array sub-bottom profiler system in the laboratory, the pool and the sea, theexperimental results and data prove that the design of multibeam parametric array sub-bottomprofiler is correct and the indicators are reasonable, the working state of receiving andacquisition circuit in the bathymetry sub-system designed in the paper is stable and thetechnical indicators are as expected.