RTKLIB-based GPS localization for multipath mitigation in ITS applications

Currently, GPS and GNSS systems are the most popular means of localization in Intelligent Transportation Systems. However, widely available GPS systems suffer from precision degradation brought about by satellite availability and multipath signals. This is especially true in urban canyons, where buildings often obstruct and reflect GPS signals. In order to ignore or rectify multipath signals, previous studies have taken into account building geometries. However, computing and retrieving building geometries for entire urban areas is still impractical for most on-board localization systems. The proposed system exploits the fact that most Public Utility Buses are constrained to a single route, enabling the system to store building geometries along the entire bus route a priori. Position corrections are computed from known satellite positions and multipath signal computations on buildings along the route. A centimeter-level accurate GPS system is presented without the need for more expensive equipment.