Research On Cooperative Localization Algorithm Of Underwater Mobile Nodes

With the development of submarine autonomy and underwater acoustic communication networking,the application mode of underwater mobile nodes represented by Autonomous Underwater Vehicle(AUV)is changing towards the direction of intelligence and clustering.Information interaction and collaboration positioning are key technology for controlling and coordinating the behavior of multiple mobile nodes that constitute the Underwater Wireless Sensor Network(UWSN)to perform advanced and complex tasks.The low transmission rate,narrow channel bandwidth and high bit error rate of underwater acoustic communication lead to the problems of low network throughput and long end-to-end delay in the Media Access Control(MAC)protocol that utilizes the transmitter as the starting point to determine conflicts and collisions,which is not suitable for mobile distributed networking system with high real-time performance requirements.Making full use of the physical topology and taking consideration on the delay effect,based on the dynamic programming algorithm,as well as utilizing the receiver as the starting point to judge conflicts and collisions,this paper researches on the sequential assignment heuristic rules of the nodes’ continuous time axes for mobile distributed small-scale networking system,and a collision-free information interaction protocol is designed.Then,in view of the problem that formation change caused by the movement of mobile network nodes destroys the protocol’s robustness and effectiveness,a control strategy combining monitoring,prediction,and adjustment is adopted,which is able to dynamically adjust and maintain the protection time slots between different data packets on the receivers’ continuous time axes in each communication ranging period.The construction of the collision-free information interaction protocol relies on the physical topology of the formation and the location information of the nodes.Therefore,high-precision co-location technology is an essential prerequisite for the communication,transmission and cooperation of underwater mobile nodes.Due to the spatiotemporal asynchronous problem caused by fuzzy normalization of the nodes’ motion in the conventional static solution model,the positioning error is introduced.Indeed,this paper builds an asynchronous co-location solution model based on motion compensation and fusion of non-common point and non-synchronous ranging and speed measurement information.Finally,the output position of the co-location system is fed back into the dynamic programming algorithm of the information interaction protocol to determine whether the shortest closed path of the physical topology of the formation has qualitatively changed,and to determine whether the sequential assignment plan needs to be reset.Using MATLAB GUI custom platform to design a set of mobile small-scale networking system based on underwater acoustic communication technology to realize the polling collision-free interaction and exchange of data and information at the Media Access Control level,and the high-precision collaborative positioning visual software interface under the integrated mode of communication and ranging.The successful testing of the networking-trial software system verifies the feasibility and effectiveness of the collision-free information interaction protocol and the collaborative positioning navigation algorithm designed and studied in this paper.