PDR Research And Realization Based On Low Cost IMU In Navigation And Positioning Technology

Nowadays,positioning and navigation service brings great convenience to people's work and life.For example,Baidu Map Application provides users with a series of services such as bus transfer?car navigation and nearby service according to their real-time location information.Hence,the demands of continuity and accuracy of positioning and navigation service become more and more urgent.However,with the development of technology and transformation of lifestyle,people spend a large amount of time inside large buildings,such as office buildings,libraries,museums,shopping malls,etc.In these cases,the global navigation satellite system has low accuracy and even can't locate positions with severe attenuation of satellite signals.How to locate people when GNSS isn't available has become an urgent and difficult problem.The current mainstream positioning technologies include bluetooth positioning? Wi Fi positioning? ultra wide band positioning? radio frequency identification positioning?pedestrian dead-reckoning positioning,etc.Since the inertial measurement unit has the advantages of high price-performance ratio and independence of other external devices,inertial navigation and positioning technology based on PDR has gradually become one of the most promising positioning technologies.For the difficult parts of key technologies and implementation in PDR-based inertial navigation and positioning technology,the following aspects are studied thoroughly in this paper:(1)The research on key technologies in PDR-based navigation and positioning technology.Since the IMU we use is consumer-level,the raw data on the movement of pedestrian collected from inertial sensing module has low accuracy;The movement of pedestrian is divided into single step units and the decomposition method of gait cycle has significant influence to the precision of PDR-based navigation and positioning system;The factors such as cumulative increase of errors can affect the accuracy of the system.This paper first presents the research on key technologies in PDR-based navigation and positioning system such as transformation of coordinate systems?zero velocity updates and Kalman filter.(2)The research on three core parts(gait detection?step length calculation and heading estimation)in PDR system.According to the principles of pedestrian dead reckoning,we have to obtain the direction and distance of the movement of pedestrian in order to locate the position preciously.Thus,we study in depth on some common methods for gait detection?step length calculation and heading estimation in this paper.We also design some experiments to verity the accuracy and improve the classic algorithms,and propose a step length estimation algorithm based on D-ZUPT.(3)The research on the design of PDR-based indoor positioning system for pedestrians.Due to the lack of mature experimental platform for PDR-based indoor positioning system,the accuracy of positioning and navigation can be affected easily by the environment.Based on the research achievements in this paper and actual demands,we complete a low-cost design of IMU and PDR-based indoor positioning system for pedestrians proposed in this paper,the performance of our PDR-based system is proved in EVAAL international competitions on indoor localization and indoor activity recognition in 2016.