Design And Implementation Of Vehicle Positioning System Error Correction Based On Connected Vehicle

With the enhancing of people's travel desire,traffic problems are becoming people's focus.Connected vehicles as an important application in IOT(Internet of Things),it's not only a very important sign of intelligent vehicles,but also a hot spot of present research.Vehicle positioning system is critical to connected vehicles.With the development of intelligent vehicles,autonomous vehicles are becoming the focus.In order to make vehicles highly intelligent,accurate positioning is definitely required.However,low cost GPS(Global Positioning System)receivers used in automotive applications suffer from low accuracy and frequent signal outages.Because that GPS receivers which are close to each other,are affected by the various sources of errors in a similar way,DGPS(Differential GPS)eliminates common mode errors to improve positioning accuracy by this feature.Though the accuracy of DGPS can be within centimeters and it is satisfied with autonomous vehicles positioning applications,it is a pity that this approach is therefore very expensive in terms of a large number of reference stations infrastructure and it requires a communication link between the reference stations and the mobile GPS receivers.Therefore,these two constraints make the DGPS difficult to use for vehicle positioning in automotive applications.With the recent emergence of wireless communication and Vehicular Ad-hoc Networks,cooperative positioning is becoming an attractive alternative for improving positioning accuracy.In this paper,the basic idea is to extend the DGPS method by using mobile reference stations instead of fixed one.In order to get better vehicle positioning estimation,it can combine the nearby vehicle information to acquire correction and broadcast to other vehicles by connected vehicles.It called dynamic base station DGPS.Each vehicle is a node in the network of vehicles and each node can act as a mobile base station..Combining with current connected vehicles technology and vehicle positioning research technology at home and abroad,paper analyzes the demand of function that collecting the vehicle positioning data and designs the collecting positioning data system of connected vehicles.In order to improve vehicle positioning accuracy by cooperative positioning,paper proposed a positioning correction method assuming that each vehicle drives in the middle of road.This method is similar to map matching.First,it uses probability statistics to make sure the error area of vehicle GPS measuring position.To make calculation faster and better real-time characteristics,the error ellipse is converted into minimum rectangle which can surround the ellipse.To make sure the vehicle is moving on which road,paper uses D-S evidence theory to calculate the basic distribution function with different weights of vehicle position and direction when the vehicle is moving on different states.Paper uses projection method to correct the vehicles position to the right way.This method eliminates common mode error to improve GPS accuracy.By analyzing the math features of errors,paper generates common errors and non-common errors with Gaussian distribution.After analyzing the influence of error sources,there comes a moving-average filter to work on the common mode errors.Not only under the condition of common errors but common errors and non-common errors,paper makes the real road system vectorization and builds a valid model to simulate the correction of positioning information which is generated randomly in Matlab.If they are effective,they can be used to correct the vehicle positioning information in the real world from data acquiring system.In this paper,the road information measured by mobileye system acts as the ground truth of vehicles.By comparison,the correction outcomes validate the availability of proposed correction method.