Research On Cooperative Navigation Method For Multiple UUVs

With the exploration and development of marine resources,unmanned underwater vehicle(UUV)has been more and more used in various marine operations because of its flexible use,high concealment and good adaptability.The stable,reliable and highprecision underwater navigation system is the prerequisite for UUV to perform underwater tasks.However,traditional underwater navigation methods cannot be used,and compared with land navigation,underwater navigation is more complex and dynamic.In view of the lack of navigation means and low positioning accuracy in the process of multi-UUVs cluster operation,this paper applies nonlinear filtering algorithm,and considers the constraints of underwater communication delay.And the filtering algorithm,formation configuration and positioning performance of multi-UUVs cooperative navigation are studied in order to improve the navigation accuracy.Firstly,based on the underwater scenes of the collaborative operation of UUV,the basic working principle of multi-UUVs cooperative navigation is studied and the characteristic of different formation structures is analyzed.Then,the kinematics model and the measurement model are set up according to the working principle of single-main multi-UUVs cooperative navigation based on distance information.Then,this paper studies the cooperative navigation algorithm of nonlinear Kalman and particle filter.Under the ideal communication condition,for nonlinear multi-UUVs cooperative navigation system,the cooperative navigation filtering methods based on Extended Kalman Filter(EKF),Unscented Kalman Filter(UKF)and Cubature Kalman Filter(CKF)are proposed respectively and derived in detail,the main steps of cooperative navigation filtering algorithm are given and the simulation comparsion is made.The simulation results show that the three algorithms are all effective for the single-main multi-UUVs cooperative navigation problem.In terms of positioning accuracy and stability,CKF is the best,UKF is the second,and EKF is the worst.Aiming at the delay problem of underwater acoustic communication between multiUUVs,this paper takes the underwater acoustic communication delay factor into consideration in the algorithm,studies the collaborative navigation algorithm based on time-delay Extended Kalman Filter(DEKF),corrects the error caused by measurement information delay,and verifies the effectiveness of DEKF algorithm by simulation.Then,the relationship among the formation configuration,observability and positioning performance of the cooperative navigation system is discussed.The observability of the single-main multi-UUVs system is analyzed,and the formation configuration optimization is carried out.The optimal formation configuration characteristics of the single-main system are pointed out.By means of MATLAB simulation and theoretical analysis,the performance of multi-UUVs cooperative navigation and positioning are analyzed.The effects of system observability,distance measurement noise and deadreckoning error on positioning accuracy are discussed.Finally,this paper introduces the system structure of the collaborative navigation experimental platform,which takes the unmanned boat as the carrier and DSP/FPGA as the core processor,and analyzes its main hardware in detail.The platform is used to design the collaborative navigation experimental scheme and carry out the lake experiment in the Heilongtan Reservoir.It is concluded that the DEKF algorithm with communication delay compensation can realize the cooperative navigation among multiple unmanned platforms.