Vehicular node positioning based on Doppler-shifted frequency measurement on highway

Vehicular node positioning needs to be quick and precise on highway for safety consideration. In this paper, we present a novel and practical vehicular node positioning method which can achieve a higher accuracy and more reliability than the existing global-positioning-system-based positioning solutions by making use of Doppler-shifted frequency measurements taken by vehicular node itself. This positioning method uses infrastructure nodes which are placed on the roadside every several kilometers as radiation sources to estimate the relative distances of vehicle to the infrastructure node. Through coordinate conversion, we get the absolute coordinates of vehicular node based on known absolute coordinates of infrastructure node. We also analyze the optimal distance of neighbor infrastructure nodes in order to ensure a high accuracy. In addition, simulation results demonstrate that the accuracy of our method with Extended Kalman Filtering (EKF) is superior to the method without EKF.