Research On Indoor Positioning And Location Privacy Protection Algorithm Based On Ultra-wideband

With the development of science and technology,the global positioning system in outdoor positioning has been widely used.However,the global positioning system cannot reach the positioning service of the indoor environment,and cannot meet the increasing demand for indoor positioning and the like.According to the surveys of academia and industry,the current indoor positioning technologies such as infrared,Bluetooth,ultrasonic,and FRID are slightly lower than people's requirements in terms of positioning accuracy and anti-interference ability.Ultra-wideband(Ultra Wide Band,UWB)technology has high transmission rate,low transmission power,good anti-interference ability and strong penetration ability,and has good transmission and positioning effect in a Line of Sight(LOS)environment with few obstacles.However,in a non-line of sight(Non-Line of Sight,NLOS)environment,multipath effects can cause errors and affect positioning accuracy.Therefore,it is a challenge to study how to eliminate NLOS errors and improve the accuracy of 3D indoor positioning in the NLOS and LOS coexistence environment.Indoor positioning can provide services such as precision marketing,public safety,and emergency rescue,at the same time sensitive information contained in the user's location may leak out.In order to solve the above two problems,this thesis aims to improve the NLOS error elimination and three-dimensional indoor positioning accuracy in the NLOS and LOS coexistence environment,and achieve real-time location privacy protection.On the one hand,NLOS error elimination in the coexistence environment of NLOS and LOS improves the accuracy of three-dimensional indoor positioning.In this thesis,a method designed for identifying and discarding unwanted signals in a three-dimensional environment where NLOS and LOS coexist,and used for localization through a CHAN algorithm based on residual weighting.The NLOS error eliminated according to the different characteristics of the NLOS and LOS pulse signals through the IEEE 802.15.4a channel model with 2-10 GHz frequency sweep range,and the algorithm is simulated by simulation of the residual weighted CHAN algorithm on Matlab.In the three-dimensional simulation experiment,the ranging accuracy is stable at 2-15 cm in the vertical 80 m range.On the other hand,it resists attacks and protects user's location privacy.First,the fog server in replace of the anonymous server between the user and the service provider based on the trusted third-party structure,which is used to solve the performance bottleneck and the trouble of being centralized attack based on the trusted third-party centralized structure.Secondly,the location fuzzy algorithm based on Hilbert encryption can solve the problem of privacy protection security through the fog server,reducing the risk of users be harassed by spam recommendation information because of location information leakage.The selection of the order coefficients in the Hilbert encryption function simulated on Matlab,which proves that when the Hilbert order is less than 10,it is the most suitable for location privacy protection encryption.Then simulating WKNN algorithm to recommend points of interest(POI)to users.This thesis analyzes the ability of the algorithm in this thesis to resist attack in three situations.