Performance Evaluation of BDS/GNSS Single-Frequency Precise Point Positioning with Ionospheric Constraint in Polar Regions

BDS/GNSS single-frequency Precise Point Positioning (SFPPP) is a major mean to ensure the navigation capability of marine vehicles in polar regions. The sophisticated polar ionosphere significantly impacts the performance of SFPPP. In general, the ionosphere-estimated and ionosphere-weighted models are commonly used for processing the ionospheric delay in SFPPP application. The traditional ionosphere-weighted model sets the empirical constraint to the strength of the ionospheric constraint. The static and kinematic positioning accuracies can be several meters by applying inadequate empirical constraint in polar regions. An ionospheric constraint impact factor is constructed to determine the reasonable ionospheric constraint. Hence, the polar BDS/GNSS SFPPP considering the ionospheric constraint is proposed. The results reveal that the static and kinematic positioning accuracy of GPS, GLONASS, and Galileo are superior than 0.3 m and 1.0 m, respectively. Moreover, the static and kinematic positioning accuracy for BDS are superior than 0.9 m and 2.3 m. Reasonable ionospheric constraint can improves the positioning accuracy and fasten the convergence. The results of 32 high-latitude stations indicate that the static and kinematic positioning accuracy of the two models can reach 0.15 m and 0.5 m. The convergence time of the ionosphere-weighted and the ionosphere-estimated models can reach 3 min and 10 min, respectively. Multi-GNSS has superior positioning accuracy and faster SFPPP convergence.