Leveraging Smart Tunnel Systems: V2X-Driven Positioning for CAVs in GNSS-Denied Scenarios

Connected and Automated Vehicles (CAVs) are revolutionizing road transport by offering enhanced safety, efficiency, and sustainability. A key requirement for their safe operation on roads is the availability of highly accurate positioning information with ultra-low latency. This study presents the design and assessment of an infrastructure-based vehicle positioning system, focusing on the latency involved in transmitting position information to vehicles using Vehicle-to-Everything (V2X) connectivity. Specifically, we consider a roadside positioning infrastructure that integrates an Ultra Wideband (UWB) technology for positioning and an ITS-G5 V2X connectivity for communication. We measure and analyze the round trip time of the V2X communication link to gain insights on the latency performance. The positioning performance is also analyzed by comparing the trajectory followed by the vehicle with the one planned by the onboard control system. On-field evaluations are conducted in a highway tunnel, demonstrating the ability of the infrastructure localization system in successfully enabling autonomous navigation.