Multi-buoy Underwater Acoustic Positioning System Signal Acquisition And Time Delay Estimation Algorithm Implementation

The buoy unit of multi buoy underwater acoustic positioning system is the working equipment for receiving,collecting and processing acoustic signals.It is responsible for time delay estimation of the signal transmitted by the cooperative acoustic beacon,and transmits the result data to the shipborne measurement and control platform through radio communication to locate the acoustic beacons in three dimensions.This paper mainly focuses on the design and implementation of broadband signal reception,system control and time delay estimation algorithm according to the actual needs of buoy unit.Firstly,aiming at the indices and functional requirements of buoy unit in multi buoy underwater acoustic positioning system,this paper has been determined the overall scheme of buoy unit,and the schemes of the buoy receiving hardware circuit,system control and signal processing platform are further designed.Secondly,this paper mainly designs and simulates the broadband bandpass filter circuit,hydrophone section and electronic cabin section amplification circuit,digital to analog and analog-to-digital conversion circuit,power supply circuit of receiver,etc.in receiving hardware circuit of the buoy unit according to the broadband receiving hardware circuit scheme and indices,and rational design of receiver PCB layout and routing is completed.This paper uses the programmable So C integrating FPGA and ARM as the core processor,and design the peripheral auxiliary circuit of the platform according to the scheme and requirements of the system control and signal processing platform.Next,this paper completed the rational design of PCB layout and routing.The system control functions such as signal acquisition,automatic gain control and serial port transceiver are developed in FPGA and verified by simulation.Next,this paper designed the algorithm flow including threshold comparator and width discriminator based on pulse splitting principle to detect the preamble pulse,and matched filter and decider based on historical values to detect pulse for measuring distance and pulse for measuring depth.This paper realized the function of the above algorithm in FPGA and carried out the pool experiment verification.Finally,this paper completes the tests and joint debugging of the circuits of each part of the buoy in the laboratory,and all functions are normal.Then,the field experiments including Songhua Lake and Shuibuya are carried out,and the joint debugging is carried out with the whole multi buoy underwater acoustic positioning system.The buoy unit works stably,and all indexes meet the design requirements.The outfield operation of the system is in good condition.