Leveraging Latitude-Differentiated Thresholds and Weight Optimization to Mitigate the Impacts of Ionospheric Scintillation on GNSS PPP

The ionospheric irregularities of the plasma density could significantly cause fluctuations of the intensity, phase, angle of arrival, and polarization state of trans-ionospheric GNSS signals in a rapid and stochastic manner, i.e., ionospheric scintillation, which could lead to communication errors and signal distortions, further seriously threatening the security of the GNSS system and affecting the performance of GNSS high-precision positioning services. Therefore, the mitigation of its impact on the GNSS high-precision positioning service has been a key scientific issue in the field of satellite navigation.

In this study, we proposed a TurboEdit cycle slip detection threshold adjustment method that considers scintillation differences at different latitudes, and constructed a stochastic model considering the ionospheric scintillation information. Through the distribution of cycle slips with regard to the scintillation index, the cycle slip threshold method is initially established for various latitudes; the ionospheric scintillation index calculated from the geodetic GNSS observations is used to construct a stochastic model, which can assign more reasonable weights for the GNSS observations affected by the ionospheric scintillation. Results show that compared with the empirical cycle slip detection threshold, the adjusted cycle slip detection threshold can significantly improve the performance of PPP positioning results in various regions under ionospheric scintillation conditions. Compared with the elevation-angle stochastic model, the improved stochastic model can mitigate the effects of the ionospheric scintillation on PPP solutions in the equatorial ionization anomaly region. This study contributes to enhancing the accuracy, reliability, and integrity of high-precision GNSS applications and services.