Ship Noise Data Acquisition System Based On Vector Hydrophone

With the development of economy and science and technology,the pace of developing and utilizing marine resources in the world has been accelerating,and a large number of offshore operation platforms have emerged.Especially the increasing number of offshore oil fields will cause huge economic losses,serious casualties and adverse social effects once they are hit by illegal ships.Therefore,ship management and control in the sea area near the offshore operation platform is becoming more and more important.The application of vector hydrophone to ship azimuth estimation is currently a relatively efficient method.Vector hydrophone can acquire not only the sound pressure information of underwater target,but also the vector information of its velocity and acceleration,just like traditional acoustic pressure hydrophone.From these vector information,the orientation information of the target can be excavated,which will play an important role in the control of illegal ships at sea.In view of the Appellate situation,this paper aims to study the ship noise data acquisition system which can be applied to vector hydrophone direction finding.This paper mainly introduces the following aspects:Firstly,the principle of active and passive sonar and their similarities and differences are introduced.At the same time,the sensitivity and phase characteristics of vector hydrophone used in this system and the background knowledge of ship noise are introduced.Secondly,the analog circuit of the acquisition system is introduced.Based on the analysis of the characteristics of vector hydrophone and ship noise,the gain design block diagram and the design of the analog signal conditioning circuit in stages are proposed,including the first-level instrument amplifier circuit,low-pass analog filter circuit,adjustable gain control circuit and post-amplifier circuit.As for the digital acquisition circuit of the acquisition system,this paper presents a 16-channel synchronous continuous acquisition system with DSP as the core of digital signal processing and FPGA as the coprocessor.At the same time,the digital acquisition circuit of the system is designed,including A/D acquisition circuit,data buffer circuit,digital-to-analog conversion circuit,Ethernet controller and interface circuit.In the aspect of application software and signal processing of acquisition system,this paper introduces the configuration of real-time embedded operating system DSP/BIOS,and designs the program of passive continuous acquisition and FIR filter based on FPGA.