An improved particle filter indoor fusion positioning approach based on Wi-Fi/PDR/geomagnetic field

The existing indoor fusion positioning methods based on Pedestrian Dead Reckoning(PDR)and geomagnetic technology have the problems of large initial position error,low sensor accuracy,and geomagnetic mismatch.In this study,a novel indoor fusion positioning approach based on the improved particle filter algorithm by geomagnetic iterative matching is proposed,where Wi-Fi,PDR,and geomagnetic signals are integrated to improve indoor positioning performances.One important contribution is that geomagnetic iterative matching is firstly proposed based on the particle filter algorithm.During the positioning process,an iterative window and a constraint window are introduced to limit the particle generation range and the geomagnetic matching range respectively.The position is corrected several times based on geomagnetic iterative matching in the location correction stage when the pedestrian movement is detected,which made up for the shortage of only one time of geomagnetic correction in the existing particle filter algorithm.In addition,this study also proposes a real-time step detection algorithm based on multi-threshold constraints to judge whether pedestrians are moving,which satisfies the real-time requirement of our fusion positioning approach.Through experimental verification,the average positioning accuracy of the proposed approach reaches 1.59 m,which improves 33.2%compared with the existing particle filter fusion positioning algorithms.

Positions Open in the Field of Plasma and Fusion

Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), one of the most important laboratories on magnetically confined fusion in China and the Nuclear Fusion Research Center of the World Laboratory, is searching for 5 senior and 10 junior scientists of plasma and fusion in the following superconducting tokamak research areas: theory and simulation, diverter and edge physics, plasma diagnostics, electron cyclotron resonant heating, ion cyclotron resonant heating, lower hybrid wave, neutral beam injection, reactor design, fusion material, superconducting engineering.

Positions Open in the Field of Plasma and Fusion

Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), one of the most important Laboratories on magnetically confined fusion in China and the Nuclear Fusion Research Center of the World Laboratory, is searching for 5 senior and 10 junior scientists of plasma and fusion in the following superconducting tokamak research areas: theory and simulation, diverter and edge physics, plasma diagnostics, electron cyclotron resonant heating, ion cyclotron resonant heating, lower hybrid wave, neutral beam injection, reactor design, fusion material, superconducting engineering.

Positions Open in the Field of Plasma and Fusion

Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), one of the most important laboratories on magnetically confined fusion in China and the Nuclear Fusion Research Center of the World Laboratory, is searching for 5 senior and 10 junior scientists of plasma and fusion in the following superconducting tokamak research areas: theory and simulation, diverter and edge physics, plasma diagnostics, electron cyclotron resonant heating, ion cyclotron resonant heating, lower hybrid wave, neutral beam injection, reactor design, fusion material, superconducting engineering.

An Indoor Localization Approach Based on Fingerprint and Time-Difference of Arrival Fusion

In this paper,an effective target locating approach based on the fingerprint fusion posi-tioning(FFP)method is proposed which integrates the time-difference of arrival(TDOA)and the received signal strength according to the statistical variance of target position in the stationary 3D scenarios.The FFP method fuses the pedestrian dead reckoning(PDR)estimation to solve the moving target localization problem.We also introduce auxiliary parameters to estimate the target motion state.Subsequently,we can locate the static pedestrians and track the the moving target.For the case study,eight access stationary points are placed on a bookshelf and hypermarket;one target node is moving inside hypermarkets in 2D and 3D scenarios or stationary on the bookshelf.We compare the performance of our proposed method with existing localization algorithms such as k-nearest neighbor,weighted k-nearest neighbor,pure TDOA and fingerprinting combining Bayesian frameworks including the extended Kalman filter,unscented Kalman filter and particle fil-ter(PF).The proposed approach outperforms obviously the counterpart methodologies in terms of the root mean square error and the cumulative distribution function of localization errors,espe-cially in the 3D scenarios.Simulation results corroborate the effectiveness of our proposed approach.

Positive Q-Value Neutron Transfer Mediated Sub-Barrier Fusion Reactions

Positive Q-value neutron transfer mediated sub-barrier fusion reactions are studied with an empirical coupled channels model, which takes into account neutron rearrangement related only to the dynamical matching condition with no free parameters. Fusion cross sections of collision systems ^32S＋^90,94,96Zr are calculated and analyzed. Logarithmic residual enhancement （LRE） is proposed to evaluate the discrepancy between calculated results and experimental data. The experimental data can be described well with this model for the first time as a whole, while the LRE analysis shows that there are still theoretical systematic deviations.

Structure and performance analysis of fusion positioning system with a single 5G station and a single GNSS satellite

NaGlobal vigation Satellite System(GNSS)positioning technology is widely used for its high precision,global,and all-weather service.However,in complex environments such as urban canyons,GNSS performance is often degraded due to signal occlusion and even fails to achieve positioning due to the insufficient visible satellites.Because of the characteristics of large band-width,low latency,and high Base Station(BS)density,the fifth-Generation mobile communication(5G)technology has gradually become a trend for positioning in cities while offering traditional communication service.To supply the communication demands of the User Equipment(UE),only one BS is usually considered to establish a connection with the UE during the BS construction.However,the positioning accuracy with a single BS in urban canyons will be significantly reduced.To further improve the positioning accuracy in such extreme scenarios,this paper proposes a simplified 5G/GNSS fusion positioning system architecture using observations from only a 5G BS and a GNSS satellite.In this system,the GNSS receiver is mounted on the 5G BS,and the measurements provided by the receiver are used to form the differential code and complete the position estimation.The positioning mathematical models of the system based on the original code and differential code are derived.Then,the impacts of the measurements noise and the time synchronization error on the positioning accuracy are analyzed theoretically.Finally,the positioning performance is investigated by a set of simulation experiments.Numerical results show that under the existing 5G measurement noise and 2 m’s code measurement noise,the improvement of the differential code based fusion positioning compared with the 5G-only positioning is more than 32%,which is also about 6%higher than the original code based fusion positioning.Besides,this improvement is not affected by the time synchronization error between the BS and the GNSS satellite.

Systematic analysis of fusion barrier heights and positions for proton projectiles using the single folding model

The nuclear potentials between protons and different target nuclei are calculated by using the single folding model with the density-dependent nucleon-nucleon interaction.The fusion barrier heights and positions for proton projectiles fusing with different target nuclei with masses from 51 amu to 139 amu are systematically shown,with charge numbers and root-mean-square radii of the interacting nuclei.The parameterized formulas for the fusion barrier height and position are obtained for proton projectile fusing with the different nuclei.The calculated results of parameterized formulas are compared to empirical values,as well as those of the proximity potential and AkyüzWinther（AW） potential.It is shown that the calculated results agree perfectly with theirs.The parameterized formulas can reproduce the exact barrier heights and positions for proton fusion systems.

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.