Communication And Navigation Integrated Wireless Ad-Hoc Network Construction And Assisted Pedestrian Positioning

With the advent of the internet of things（IOT）in recent years,location-based services（LBS）have permeated every aspect of social activity,and there is a growing demand for indoor positioning.Ultra-wideband（UWB）is capable of obtaining high accuracy distance,but is severely affected by multi-path and non-line of sight（NLOS）.Pedestrian dead reckoning（PDR）has strong anti-interference capability and can accurately estimate relative motion changes in the short term,but the error disperses over time.The advantages of the two technologies complement each other,and through information fusion,high accuracy and stable positioning results can be obtained.Meanwhile,the indoor environment is complex and volatile,and it is crucial to build a positioning basis quickly.Localization solutions based on wireless ad-hoc network are flexible and easy to implement,and may be able to solve localization problems in harsh or unknown environments.Therefore,this paper proposes a scheme to construct wireless ad-hoc network with integrated communication and navigation and assist pedestrian positioning,which can establish localization benchmarks quickly in target scenes and achieve pedestrian fusion positioning.In this paper,the main work is as follows:（1）Propose adaptive peak detection algorithm,which adaptively determines the threshold value for detecting peaks according to the motion data collected by different users at different speeds,effectively alleviate the problem of false detection and missed detection with fixed peak threshold;and,combine gyroscope,accelerometer,and magnetometer to implement heading estimation algorithm based on magnetic interference detection and external acceleration detection,suppressing the effects of errors such as sensor drift,noise and small jitter.（2）Introduce several common UWB positioning mechanisms and NLOS detection methods;Using Deca Wave’s DWM1001-DEV for two-way-ranging（TWR）,and collecting data at multiple sets of distances to perform UWB anchor node distance calibration.The results show that there is a centimeter-level ranging accuracy with no human interference.（3）Introduce the PDR-assisted UWB wireless ad-hoc network construction process proposed in this paper.The initial position of unknown anchor nodes and the heading between adjacent anchor nodes are obtained by PDR,the distance between anchor nodes is measured by TWR;and the constraint information of heading and distance is used to realize the adjustment of the traverse network for precise positioning of anchor nodes.Two configuration options for two typical indoor scenarios are introduced,and the results of field tests show that the proposed method constructing wireless ad-hoc network with integrated communication and navigation can achieve a decimeter-level accuracy of base station calibration.（4）An adaptive particle filter（APF）fusion algorithm based on outlier detection is proposed to fuse the step and heading from the PDR,as well as the distance information from the UWB.An abnormal range detection method is derived from the chi-square test,and the variance of measurement noise is adjusted dynamically.A device integrating the WT931 attitude sensor and the DWM1001-DEV development board is designed and data is collected to experimentally validate the proposed method.The results prove that the adaptive particle filtering algorithm proposed in this paper has higher accuracy in both simple and complex environments.In the complex environment,the 95% error is 0.54 m.Compared with PDR,least square（LS）,and conventional particle filter（PF）,the APF error is reduced by more than 70%.Moreover,after the introduction of the anchor error,the average error of APF in the complex environment is only increased by 0.09 m.This indicates the feasibility and effectiveness of the proposed construction and positioning scheme.