A Method to Mitigate the Effects of Strong Geomagnetic Storm on GNSS Precise Point Positioning

Abstract

When solar events such as solar flare, coronal mass ejection, and coronal hole high-speed flow occur, the highspeed plasma clouds ejected from the sun surface will propagate into Earth's space through the interplanetary space, press the magnetosphere and inject abundant solar wind energy into Earth's magnetosphere, resulting in geomagnetic field disturbance. This phenomenon is referred as to geomagnetic storm (Gonzalez et al., 1994). According to the minimum value of 𝐴𝐴 Dst index, the geomagnetic storm is generally classified as four different intensity levels as weak geomagnetic storm (−50 < 𝐴𝐴 Dstmin ≤ −30 nT), moderate storm (−100 < 𝐴𝐴 Dstmin ≤ −50 nT), strong storm (−200 < 𝐴𝐴 Dstmin ≤ −100 nT), severe storm (−350 < 𝐴𝐴 Dstmin ≤ −200 nT) and great storm ( 𝐴𝐴 Dstmin ≤ −350 nT; Loewe & Prölss, 1997).Under geomagnetic storm, the rapid penetration of magnetospheric electric field can lead to the sharp increase of ionospheric total electron content (TEC) as well as the irregular variations of ionospheric TEC, thus affecting the performance of precise positioning of Global Navigation Satellite System (GNSS; Astafyeva et al., 2014;

ROTI‐Based Stochastic Model to Improve GNSS Precise Point Positioning Under Severe Geomagnetic Storm Activity

“…It is known that under severe disturbances, GNSS satellite signals could encounter cycle‐slips or even loss of lock. Only relying on stochastic model cannot maintain high‐precision results (Luo et al., 2022). However, under this extreme condition, scheme 3 PPP results are also slightly better than these of schemes 1 and 2.…”

“…We select only GNSS satellites with the elevation angle larger than 15° for calculation and use the TurboEdit algorithm to detect and correct the cycle slips (Blewitt, 1990). The thresholds of the Melbourne‐Wübbena (MW) combination and the geometry‐free (GF) combination are set as $${Th}_{MW}=1\,cycle$$, and $${\,Th}_{GF}=0.5\,\mathrm{m}$$ (Luo et al., 2022; Zhang et al., 2014).…”

“…The solar wind and its interaction with the magnetosphere‐ionosphere‐thermosphere system can cause severe disturbances in the global near‐Earth space environment. When solar activities, such as coronal cavity high‐speed flow and coronal mass ejection occur with numerous high‐speed plasma clouds, reach near‐Earth space through the interplanetary medium and interact with the Earth's geomagnetic field, a large number of charged particles carried by the high‐speed solar wind flow can inject into the ionosphere, resulting in severe global geomagnetic disturbance, and then triggering geomagnetic storm occurrence (Cherniak et al., 2015; Gonzalez et al., 1994; Luo et al., 2022).…”

“…In view of the possible interference of geomagnetic storms and corresponding ionospheric disturbances on GNSS signals, researchers have tried different methods to improve PPP accuracy during storm environment, which can be basically summarized into three categories: (a) using multi‐GNSS satellites observations to improve the geometry strength of satellites (Liu et al., 2018; Yigit et al., 2014); (b) establishing the cycle slip detection threshold model to reduce the false detection rate of cycle slip under storm conditions (Luo et al., 2022); (c) developing stochastic model to assign appropriate weights of GNSS measurements under disturbed geomagnetic environments (Aquino et al., 2009; Guo et al., 2021). The first two strategies have been confirmed to be effective in GNSS PPP during storm periods.…”

A Novel Ionospheric Disturbance Index to Evaluate the Global Effect on BeiDou Navigation Satellite System Signal Caused by the Moderate Geomagnetic Storm on May 12, 2021

“…If the carrier phase observations in two or more frequency bands are not out of loss, the difference between the product of the dual-frequency carrier phase observations and wavelengths tends to be a smooth curve. However, under the influence of geomagnetic storms, irregular changes in satellite carrier phase observations, which are affected by the inhomogeneous structure of the ionosphere, could change this regularity [ 30 ]. Following the “phase slip” idea from Afraimovich et al [ 13 , 14 ], the dual-frequency carrier phase observation combination calculated by Equation (4), that is the Geometry Free (GF), is used for the detection of anomaly satellite signals affected by ionospheric irregularities.…”