Cooperative Validation of CAM Position Information Using C-V2X

Cellular-Vehicle-to-Everything (C-V2X) communication is an essential component of future automated traffic systems as well as a promising technology for mobile robot applications. In those scenarios, the vehicles typically exchange location data obtained by on-board positioning modules such as satellite receivers or sensor-based SLAM (Simultaneous Localization and Mapping). As such information is vital for cooperative applications, its validation is an important safety feature. In this paper, we propose a method to repurpose available information from C-V2X to estimate the distance between sender and receiver. By analyzing the timing of Cooperative Awareness Messages (CAMs) within the C-V2X resource grid it is possible to derive fairly accurate distance information, which can be used to validate the location data contained within the payload. Such validation is helpful in case of technical failures of positioning modules or intentional transmission of fraudulent location data. Our analysis based on MATLAB simulation shows a positioning error of 30 m for typical traffic and robot scenarios. One key learning is that existing C-V2X signal information can be used to achieve this performance even in the presence of multipath fading. Although the positioning is not yet precise enough for stand-alone use, it is useful for overall safety and reliability measures in cooperative vehicular and robotic applications.