Multibeam Sonar Receiver And Signal Processing Algorithm Implementation

With the proposal of the strategic goal of " building a maritime power," the field of marine exploration has received more and more attention.As one of the key equipment of ocean exploration,multi-beam bathymetric sonar has the advantages of high measurement accuracy and wide coverage.It has a very broad application prospect in underwater topographic mapping,sediment salvage,seabed depth measurement and other fields.In view of the fact that most of the current domestic multi-beam sounding sonars are arcshaped transmitting arrays,which is not conducive to the conformal design of underwater platforms when performing underwater detection tasks,this paper carries out research on multibeam sounding sonar using three linear arrays to form a transmitting array.Based on the multibeam sounding sonar system developed by the project team,this paper mainly completes the design and implementation of multi-channel receiver and real-time digital signal processing algorithm at the receiving end of sonar.Firstly,according to the application scenarios and actual requirements of multi-beam sounding sonar,the relevant technical indicators of the receiving end are given.Then,according to the indicators,the multi-channel receiver and real-time digital signal processing scheme are determined,and the key parameters are analyzed and demonstrated.Then the design of multichannel receiver and signal processing algorithm is discussed in detail.At the analog end,the schematic design and simulation of 108 channel receiving signal conditioning circuit and A/D conversion circuit are completed,and the PCB drawing is completed according to the schematic and the internal structure of the receiving cabin.On this basis,the circuit noise and power consumption are minimized.At the digital end,the overall architecture of the acquisition and processing functions realized by the acquisition FPGA and the processing FPGA is determined.According to this structure,the logic programming of A/D acquisition,serial port reception and command solving,as well as the FPGA implementation of signal processing algorithms such as orthogonal transformation,polyphase filtering,matched filtering and beamforming for multiple frequency received signals are completed,and the effect of algorithm implementation is verified by simulation.In the case of ensuring the accuracy of the algorithm processing results,the program is further optimized in terms of timing convergence,resource consumption,and portability.Finally,the circuit modules of the receiver and the signal processing flow are tested in detail,and the overall performance of the system is further tested through system joint debugging and pool experiments to verify the stability and reliability of the system.The test results show that the work done in this paper meets the design requirements.