We live in an age of growing autonomy that contributes to a smart society. However, autonomy is not without its risks and those risks are most acute in autonomous vehicles both on the ground and in the air. There is a real global and UK drive to ensure that air- and ground- autonomous vehicles can deliver social good, but this must be achieved to the correct levels of: reliability, safety, and economic efficiency. Position, Navigation & Timing (PNT) data is critical to ensure that autonomous vehicles operate safely, especially when in cohabitation with human-operated systems. Whilst we have traditionally relied on a Global Navigation Satellite System (GNSS) or terrestrial assisted GNSS, we know that urban shadows and adversarial attacks can make PNT data unreliable, increasing the chance of collisions. Our reliance on accurate PNT data has never been greater, where small errors in time can lead to a corresponding miscalculation in space between fast-moving vehicles. This project has the ambition to establish the evidence base for redistributing PNT data to air and ground autonomous systems in a smart city infrastructure environment and demonstrate the cyber-physical technologies required for safe, reliable, and secure autonomous transport.