Comprehensive Analysis of the Cycle Slip Detection Threshold in Kinematic PPP During Geomagnetic Storms

Space weather events may affect the magnetosphere and ionosphere, and thus reduce the positioning capacity of global navigation satellite systems. The paper analyzes the BDS/GPS kinematic Precise Point Positioning (PPP) accuracy during the November 2021 geomagnetic storm to investigate the impact of the cycle slip (CS) detection on positioning accuracy under an active ionosphere. The results show that when using the conventional constant threshold of geometry-free (GF) CS detection, several stations in high latitudes present obvious accuracy anomalies and the maximum positioning error reaches 6 m. It is also found that the CS incidence increases significantly during the period of accuracy anomalies. When using the adaptive GF threshold, the kinematic PPP positioning accuracy and CS incidence return to the normal level, which proves that the underprivilege of conventional GF threshold that the geomagnetic storm could generate CS misjudgments and lead to an abnormal positioning accuracy. The average 3D positioning accuracies of 40 stations worldwide located at different latitudes show that the adaptive GF threshold could improve the average positioning accuracy of stations in high latitudes by 42.5%.