High latitude ionospheric disturbances: Characterization and effects on GNSS precise point positioning

High latitude ionospheric irregularities of various scale sizes, which are mostly driven by the coupling processes between the solar wind and Earth´s magnetic field, frequently result in phase scintillations over auroral oval and polar cap regions. Strong phase scintillations may cause a GNSS receiver to lose track of some satellites in view. Furthermore, rapid fluctuations in the ionospheric electron content may interfere with cycle slip detection and repair algorithms. These can result in degraded GNSS positioning accuracy. Similar to moving receivers, precise epoch solutions for static stations are also crucial for reliable interpretation of position estimates in applications such as earthquake monitoring. Depending on the scale size of the ionospheric irregularities causing phase scintillations, multi constellation GNSS processing can be effective to overcome decreased number of locked satellites. This is also relevant in high latitude regions with the lack of high elevation angle GPS satellites.High rate GPS phase rate measurements are monitored by the Canadian Geodetic Survey of Natural Resources Canada resulting in enhanced understanding of ionospheric irregularities´ spatial and temporal characteristics. About 160 globally distributed 1-Hz GPS stations are used in near-real-time to derive inter-frequency phase rate variation statistics. Analysis of these measurements has confirmed that ionospheric GPS phase disturbances are expected at night side of auroral oval and dayside of polar cap. However during geomagnetic storm periods such irregularities can occur during local day time over auroral zone as well as sub-auroral latitudes. This study assesses the effects of ionospheric irregularities, detected through the monitoring system, on GNSS precise point positioning (PPP) estimates. Ionospheric phase scintillation events may results in degraded repeatability in position components processed in kinematic mode. Correlation of repeatability of position estimates of stations in Canadian auroral zone with auroral electrojet (AE) index and solar wind speed are examined.