Most autonomous vehicles localize by using a point cloud map of the route with "ground truth" position data (often via GPS). The vehicle looks around and finds

Most autonomous vehicles localize by using a point cloud map of the route with "ground truth" position data (often via GPS). The vehicle looks around and finds the closest point cloud that matches the map, and makes some adjustments for vehicle state (aka pose). GNSS is usually a secondary input if it's used significantly at all.