Research On Vehicular Cooperative Positioning Technology Based On DSRC

Intelligent transportation systems(ITSs)are increasingly considered to mitigate the impacts of road transportation,such as road injuries,energy waste,and environmental pollution.Vehicular positioning is a fundamental part of many ITS applications.Although global navigation satellite systems(GNSSs),e.g.,Global Positioning System(GPS),are applicable for navigation and fleet management,the accuracy and availability of GNSSs do not meet their requirements for some applications like collision avoidance or lane-level positioning.Cooperative Positioning(CP)technology can improve the location accuracy through vehicle information exchange.Firstly,this paper mainly introduces some conceptions of cooperative positioning(CP),and analyses the traits of the conventional Cooperative positioning(CP)systems and the modern Cooperative positioning(CP)systems.In the modern Cooperative positioning(CP)systems,the kernel is the rang and rang-rate.This paper also discussed the algorithm of rang and rang-rate based on DSRC(Dedicated Short Range Communication).Secondly,aiming at the requirement of high precision relative positioning in a vehicular ad hoc network(VANET),this paper proposed an enhanced tight CP technique with INS based on tight CP.In the enhanced CP method proposed here,vehicles communite their inertial navigation sensors information,GPS pseudoranges and GPS Doppler shifts by Dedicated Short-Range Communications(DSRC).Each vehicle fuses the own metrical information and the metrical information of the other to enhance the relative positioning of vehicles.Based on the analytical and experimental results,in a full GPS coverage environment,the new tight integration CP outperforms tight CP and differential GPS by at least by 10% and 24%,respectively.In a GPS outage,the performance improvement can be up to 35% and 45% respectively.Finally,considerating the density of urban environments,the reduced quality or complete unavailability of GPS measurements challenges the effectiveness of any CP algorithm.For this purpose,a new enhanced tightly–coupled CP technique with DSRC Doppler,IMU and GPS are presented by adding the Doppler shift of the carrier of Dedicated Short-Range Communications(DSRC)signals.In the enhanced CP method proposed here,vehicles communicate their inertial measurement unit(IMU)data and GPS measurements.Each vehicle has fused the GPS measurements and IMU data and the inter-node range-rates based on the Doppler shift of the carrier of DSRC signals.Based on the analytical andexperimental results,in a full GPS coverage environment,performance of the new tight integration CP outperforms tight CP with inertial navigation system(INS),tight CP and differential GPS by at least by 6%,15%,and 28%,respectively.In a GPS outage,the performance improvement can be up to 35%,47%,and 55% respectively.