XANV/GNSS-Based Integrated Navigation Using a Robust Filtering Algorithm

In order to improve the satellite orbit determination accuracy, an X-ray pulsar-based navigation (XNAV)/Global navigation satellite system (GNSS) integrated navigation scheme is proposed. A global optimal filtering algorithm called robust federated extended Kalman filter (RFEKF) is proposed to fulfill data fusion. In this algorithm, an adaptive extended Kalman filter (EKF) with measurement noise scale factor is derived as the local filters to reduce the influence of measurement malfunctions and enhance the robustness of orbit determination system. The statistical threshold detection scheme based on the residual chi-square test is used for the fault detection. The simulation results demonstrate the validity and feasibility of RFEKF algorithm in case of measurement malfunctions.