The rise of connected and automated vehicles has created a need for robust globally referenced positioning with lane-level (e.g., sub-30-cm) accuracy (Reid et al., 2019). Much automated ground vehicle (AGV) research focuses on the use of lidar and cameras for navigation, but these sensing modalities often perform poorly in low-illumination conditions or during adverse weather such as heavy fog or snowy white-outs. By contrast, positioning techniques based on radio waves, such as automotive radar or GNSS, are robust to poor weather and lighting conditions (Narula et al., 2022). Recent work has found that fusing measurements from low-cost automotive radars with inertial sensing can provide lane-level accuracy in urban environments (Narula et al., 2022). But radar-based positioning in a global coordinate frame requires the production and maintenance of radar maps, which is a time-consuming and costly endeavor.