Passive Ranging Of Moving Target Based On Single Hydrophone

Passive positioning of underwater targets has always been a hot spot in the development of underwater acoustics.In passive positioning,the radiated sound of the target propagates through the ocean sound field,and there are both target source information and ocean environment information in the received signal of the receiving hydrophone.Therefore,it is a trend to combine underwater acoustic physics in sonar signal processing.The shallow sea low-frequency sound field has a stable interference structure,and the waveguide invariant summarizes the interference law,and the distance information of the underwater target is linked with the interference fringe,so that the interference fringe information can be used to obtain the target distance.Starting from the formation principle of the interference structure,this paper proposes a single hydrophone passive ranging method.Firstly,the theory of waveguide invariance is briefly deduced,and the effects of sound velocity gradient,seabed parameters,seamounts and sea slopes on interference fringes and waveguide invariants are analyzed and analyzed using 3D-Bellhop calculation model simulation,and the influence factors of various variables on interference fringes are compared and analyzed.size.Use image processing technology to obtain a clearer interference structure to facilitate subsequent information extraction of interference fringes.Secondly,the wave equation is used to derive the shallow ocean sound field,and the low-frequency interference ray model is constructed based on the ray theory.Since the ray theory is better for the wave theory at close range,the virtual source method is used for the near field interference analysis and the ray theory calculation model Bellhop simulation In the low-frequency close-range situation,the hyperbolic cluster distribution law of the interference fringe of the radiating target is obtained.The interference fringe is determined by the motion state of the target(speed,distance and navigation depth)and the sound field environment(sea depth,sound velocity gradient,seafloor undulation,etc.)According to the interference law of,the equivalent relationship between the invariant of the ray waveguide and the structure of the interference fringe is used to obtain the distance of the target using the interference fringe information.Finally,the normal wave theory is used to study the low-frequency and long-distance interference law,the normal wave theory model KRAKENC is used to simulate the low-frequency and long-distance situation,the sound pressure cross-spectrum method is used to obtain the radial velocity of the target movement,and the time-frequency analysis algorithm is used to improve the cross-spectrum The signal-to-noise ratio and anti-interference ability of the algorithm.Defined by the waveguide invariant,the interference fringe equation and the virtual array signal processing are used to realize the passive ranging of the single acoustic pressure hydrophone and the passive ranging of the single vector hydrophone.This paper uses different theoretical methods to realize the target short-range and long-range passive ranging,and analyzes the influencing factors of each variable,and realizes it by simulation.These technologies have important application prospects in acoustic surveying,coastline warning,passive detection and other fields.