Smartphone PDR/GNSS Integration via Factor Graph Optimization for Pedestrian Navigation

In a smartphone, the global navigation satellite system (GNSS) receiver is dominant in providing position information for users. However, GNSS signals are vulnerable to the environment, i.e., city canyons and tunnels. Pedestrian dead reckoning (PDR) exploring human walking gaits is another effective method to determine pedestrian position. Accelerometers and gyroscope sensors are available in smartphones to detect pedestrians' steps and carry out PDR. Aiming to improve smartphone position accuracy, we propose two different factor graph optimization (FGO)-PDR/GNSS integration models. First, the position from PDR and GNSS is integrated using FGO. Second, given the negative influences of the heading angle errors and the inconsistency between a smartphone and the pedestrian walking direction, PDR step length and GNSS are integrated using FGO. Android smartphones were utilized to collect different datasets and evaluate the proposed methods; experimental results indicated the superior performance of the proposed methods.