GNSS/ Visual Fusion Positioning in Urban Environment Based on Semantic Segmentation and Adaptive Filtering
摘要
Accurate and reliable location services are the fundamental key technologies for autonomous driving and intelligent transportation. Due to the strong positioning complementarity between GNSS and visual positioning, GNSS/vision combined system has been widely used in navigation and positioning fields such as robots. This research presents a loosely coupled GNSS/visual localization approach that integrates environmental semantics to mitigate the degradation of positioning accuracy in GNSS/ visual integrated systems operating in complex urban environments. Firstly, the improved YOLOv5 model was used to extract the environment semantic information in the image, and the dynamic feature points that affected the visual positioning accuracy were eliminated. Then, the occlusion of GNSS signals by buildings was evaluated through environmental semantics, and an adaptive Kalman filter model based on occlusion factors was constructed to improve the positioning accuracy of the GNSS/ vision combined system. Finally, the on-board experimental results showed that the proposed method has smaller Root Mean Square Error (RMSE) and achieves 10.7% and 9.4% higher positioning accuracy in the east and north directions, respectively, compared to a GNSS/INS/vision tightly coupled system.