Design And Implementation Of Signal Processing Software For Underwater Passive Positioning System

In recent years,with the exploration of the ocean,the importance of underwater target positioning technology has been increasing.When locating underwater targets,according to the different modes of work,underwater target positioning can be divided into active positioning systems and passive positioning systems.Different from the former,the passive positioning system has the advantages of simple implementation and no need to install cooperative beacons,so the research on passive positioning system is very necessary.The underwater passive positioning system uses the azimuth estimation results and the delay difference estimation results measured by multiple platforms to realize the horizontal positioning and depth positioning of underwater targets.Therefore,the azimuth estimation method and the delay difference estimation method of underwater passive positioning system are studied and implemented.In this paper,the signal processing method of underwater passive positioning system is studied,and a set of signal processing software of underwater passive positioning system is designed and implemented on this basis.The software is controlled by a display and control platform,using DSP to process the target radiated noise in real time.The main research contents of this paper are as follows: research on azimuth estimation method of single-vector hydrophone,research on time delay difference estimation method,design and implementation of signal processing software for underwater passive positioning system,signal processing software testing and data processing.For the passive positioning system,the azimuth estimation results are mainly used for horizontal position solving in the positioning system,and the delay difference estimation results are mainly used for depth solving.In the azimuth estimation part of single-vector hydrophone,the received signal model of vector hydrophone is first studied,and on this basis,the complex sound intensity method and weighted histogram method are studied.Then,the combined processing between the acoustic pressure and vibration velocity channels of vector hydrophones is used to study the elimination azimuth estimation method of the convolutional joint processing output channel,and the performance of the convolutional joint processing output channel negative azimuth estimation method,the complex sound intensity method and the weighted histogram method are compared and analyzed.Finally,in order to further improve the accuracy of single-vector hydrophone azimuth estimation,the Kalman filter algorithm is used to filter the position estimation results.The simulation results show that after the Kalman filtering,the azimuth estimation accuracy of the single-vector hydrophone is improved.In the part of time delay difference estimation,this paper mainly studies the time delay difference estimation method of underwater high-speed deepening moving targets.Firstly,by establishing a Doppler change model of high-speed moving targets,the correlation effect of Doppler effect on the received signals of two hydrophones is analyzed.On this basis,the Doppler compensation method is studied and simulated,and the simulation results show that the correlation between the signals is significantly improved after Doppler compensation.Then,the cross-correlation algorithm based on Doppler compensation is studied and simulated,and the simulation results show that the algorithm can solve the Doppler influence caused by the target motion,and the ideal delay difference estimation results can still be obtained when the target motion speed is high.Finally,an autocorrelation delay estimation method that can obtain the time delay difference between direct sound and primary sea surface reflection sound is studied.On this basis,the functional requirements of the signal processing software are analyzed,the appropriate signal processing method and hardware implementation platform are selected,and the design and implementation of the signal processing software of the underwater passive positioning system are completed.The design of data communication module,command execution module and signal processing module is realized on the TL-5728 platform,and the signal processing requirements of underwater passive positioning system are completed,and the functions of effective azimuth estimation and delay difference estimation of non-cooperative targets in high-speed motion can be realized.Finally,after laboratory testing and lake testing of the signal processing software of the underwater passive positioning system,it is verified that the software can meet the design requirements and achieve the expected goals.