VANETs Positioning in Urban Environments: A Novel Cooperative Approach

Location-Based Services (LBS) and Intelligent Transportation Systems (ITS) demand positioning accuracy and availability requirements. In urban canyons, Global Navigation Satellite Systems (GNSS) suffer from signal blockage, jamming , severe multipath and low Carrier-to-Noise (C/No) ratio which degrade location accuracy and availability. Therefore, applications solely relying on GNSS have limited performance. In this paper, we present a novel unified Cooperative Positioning (CP) solution which enhances positioning accuracy and availability in urban canyons. Our proposed approach is named Angle Approximation (AA). AA requires no infrastructure or other aiding sensors, AA is distributed and addresses two core challenges (limited positioning accuracy and availability) in a unified solution. AA artificially generates the hindered pseudorange by sharing angle information between vehicles using Dedicated Short Range Communication (DSRC). To enhance the performance of the AA technique, we propose and analytically derive the Absolute Sum of Double Differencing (ASODD) method which increases the probability of selecting the most accurate generated pseudorange. We experimentally evaluate the performance of the proposed system through real measurements using NovAtel receivers. We also carry out extensive simulations to demonstrate the ability of the proposed system to increase solution availability. Our experimental and simulation results demonstrate that the solution accuracy of our approach is inversely proportional to the distance between vehicles. Specifically, the mean error of the generated pseudorange is limited to 14 percent of the distance between vehicles.