Seamless Indoor-Outdoor Switching Localization Algorithm based on CKF

To solve the problem of large positioning error and discontinuous positioning of special forces members when moving in cross-region indoors and outdoors, and to compensate for the linearization error and local convergence problem that may exist in the extended Kalman filter(EKF)in nonlinear systems, that is,the iterative results may be trapped in a local optimum situation, a seamless indoor-outdoor switching localization algorithm based on cubature Kalman filter (CKF) is proposed. CKF does not require the computation of Jacobian matrices, which can improve computational efficiency and filtering accuracy to a certain extent. In the system, an inertial measurement unit (IMU) is employed to correct the positioning errors of ultra-wideband (UWB)and BeiDou navigation satellite system(BDS).The positioning data from UWB and BeiDou in cross-region are weighted fused and then fused with the data from the IMU using CKF to obtain the final accurate positioning information. This study designs a scene-switching mechanism to achieve seamless switching between indoor and outdoor positioning scenes. By jointly analyzing the positioning accuracy of UWB and BeiDou,the positioning scene is determined, and appropriate counting thresholds are set to avoid frequent erroneous scene switches. Experimental results show that the proposed algorithm achieves a positioning accuracy of approximately 21.7 cm in cross-region,which can enable seamless integration of indoor and outdoor positioning,avoid positioning jumps, and enhance positioning accuracy.

A hierarchical coordinated control strategy based on multi-port energy router of urban rail transit

The multi-port energy router(ER)is an effective topology for integrating train traction load,AC load,the energy storage system and photovoltaic(PV)energy.The start and stop process of urban rail transit trains and the access of distributed energy sources to rail transit ER lead to serious fluctuations of DC bus power,so it is necessary to route energy between different ports,involving multi-operating modes,while seamless switching is a major challenge.In this paper,a hierarchical coordinated control strategy is proposed to enable the multi-port ER to operate in a coor-dinated fashion under the conditions of train parking,acceleration,constant power driving and deceleration,and to switch seamlessly under various working conditions.The energy central dispatching layer sends working condi-tion instructions by sampling the state information of each port,while the microgrid control layer adopts central-ized control,receiving upper working condition instructions and sending drive signals to the local control layers to maintain the balanced energy flow of each port.In the local control layers,the PV adopts the improved perturbation and observation method of power control(PC-P&O),while the ES system adopts voltage loop control with an SOC influence factor,voltage loop control with switching factor and power loop control according to the different working conditions,so as to transmit the required train load power accurately and maintain the stability of the DC bus voltage.Finally,the effectiveness of the proposed hierarchical coordination control is verified by MATLAB/Simulink simulations.