Research On Underwater Target Cooperation Location Algorithm Based On Asynchronous Clock

As the country pays more and more attention to the marine field,the marine underwater acoustic sensor network also finds important value of exploration in the underwater related field.The effective positioning of underwater targets is an important application of underwater acoustic sensor networks,and its main role is to obtain the effective position of underwater targets,paving the way for further research.However,due to the existence of complex environment and noise in the underwater,the target positioning task is greatly increased.In this paper,from the perspective of achieving accurate position of underwater targets,using the advantage of underwater acoustic sensor networks,by designing a suitable sensor network and proposing an information interaction method under asynchronous clock,and the target information is re-integrated to reduce the measurement error and the influence of noise on the positioning process,and to improve the positioning accuracy of underwater targets.Firstly,aiming at the influence of the complexity of underwater environment on target location,the sensor network structure suitable for underwater targets location is proposed.According to the moving characteristics of the underwater target node(underwater submersible),the kinematics model of the target node is established,and the request-based hetero-interaction method is used to solve the problem of clock synchronization between nodes.Furthermore,the extended Kalman filter and the unscented Kalman filter localization algorithm are designed to reduce the influence of noise on the positioning accuracy and to obtain higher positioning accuracy.Secondly,aiming at the factors of the complex and changeable underwater environment and the diversity of node models,a four-degree-of-freedom target kinematics and dynamics model for target nodes is introduced.Aiming at the problem of reduced positioning accuracy caused by the unsynchronized clocks between the underwater nodes,the measurement error and the underwater noise,an extended Kalman and unscented Kalman localization algorithm based on asynchronous clock is proposed.In theory,the stability of the algorithm is analyzed,and Cramér-Rao Lower Bound is solved and compared to eliminate the measurement error and the influence of underwater noise,and to improve the positioning accuracy of underwater targets.Finally,aiming at the problem of the non-uniform distribution of underwater sound in the underwater environment and the relative movement in the target positioning process,considering the influence of the sound line bending on the target positioning,the movement compensation strategy is proposed to solve the movement error of target nodes during the positioning process.The extended Kalman filter algorithm is used to reduce the influence of measurement error and underwater environmental noise,and to further improve the positioning accuracy of underwater targets.