Barometer assisted smartphone localization for vehicle navigation in multilayer road networks

Multilayer transport structures, such as elevated roads and tunnels, are increasingly used to solve the growing traffic congestion problems in dense urban areas. It presents a challenge for navigation systems to determine which layer the vehicle is running on when elevated roads or tunnels are parallel to and close to surface roads. In this paper, we propose a smartphone-based positioning method to provide accurate position and road layer for vehicle navigation in multilayer road networks. Systemic errors of barometers are calibrated with GNSS measurements, local Digital Surface Model (DSM), and Mean Sea Level pressure. Then, barometer output absolute altitudes are integrated with GNSS and IMU to achieve 3D vehicle positioning. Using absolute altitudes, DSM, and GNSS information, the road layer can be identified without initial layer information in multilayer road networks. Experiment results demonstrate that the proposed method can provide accurate location and road layer in multilayer road networks.