Pedestrian Positioning Research Based On The Combination Of Micro Electro Mechanical IMU And UWB

With the development of the information age,it is becoming more and more important to obtain the location information of people in daily life and work,which helps people’s life services.Since people spend most of their time in indoor environments,pedestrian indoor positioning has become one of the most popular research topics.For complex indoor conditions,Pedestrian Dead Reckoning(PDR)has some advantages such as easy implementation,good autonomy,and low cost,but it will accumulate errors over time;Ultra Wide Band(UWB)Has some advantages such as high accuracy,high-speed data transmission,and low power consumption,but there are problems such as multipath interference and signal occlusion.Therefore,this paper adopts the combination of PDR/UWB,which has complementary advantages and can effectively improve the pedestrian positioning accuracy and enhance the reliability of positioning services.This article is mainly divided into three parts,namely: PDR positioning system,UWB positioning system and PDR / UWB combined positioning system.Among them,the first two parts are the research foundation of the third part,and the third part is the research focus.Each part is as follows:(1)PDR positioning system: The relevant theoretical basis of pedestrian dead reckoning is elaborated,and the three contents of gait detection,step length estimation and heading angle estimation in PDR are introduced in detail.This paper proposes the use of smoothed combined acceleration for gait detection and step size estimation,This method is simpler to implement programmatically.The IMU measurement data in the combination experiment were selected and calculated by using the PDR method,the PDR positioning accuracy of this paper is meter level.(2)UWB positioning system: tells about the signal characteristics of UWB,introduces five common positioning technologies,elaborates the least squares algorithm and Taylor algorithm,and analyzes the difference between the two positioning algorithms when linearized.This paper studies the weight distribution method in UWB positioning,and assigns weights according to distance and ranging quality to make positioning more accurate.The UWB measurement data in the combined experiment is selected,and the two algorithms of least squares and Taylor are implemented by programming.The UWB position solution is used to compare the positioning effects of the two.More than 98% of the positioning results can reach decimeter level.(3)PDR/UWB combined positioning system: It describes the commonly used filtering algorithms.Based on the PDR/UWB combined content studied in this paper,on the basis of discrete Kalman filtering,two models of loose and tight combination of PDR/UWB are established,and the two are analyzed.Different combinations.According to the data measured by the combination experiment,the two models of PDR/UWB loose combination and tight combination established in this paper are used for programming and calculation,and the two positioning effects are compared.The performance of the loose and tight combination of multiple UWB signal coverage and only one UWB signal coverage was studied respectively.The combination accuracy of the two UWB cases was analyzed,and the accuracy of the combination was decimeter level.The reliability of the combined model established.The PDR/UWB combination improves positioning accuracy compared to PDR,and enhances the reliability of positioning services compared to UWB.