Investigating the Impacts of Ionospheric Irregularities on Precise Point Positioning Over China and Its Mechanism. Issue 11 (21st November 2022)

• Record Type: Journal Article
• Authors: Li, Wei; Song, Shuli; Zhou, Weili; Cheng, Na; Yu, Chao
• Is Part Of: Space weather. Volume 20:Issue 11(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-21
• Subjects: ionospheric irregularities -- GPS -- kinematic PPP -- cycle slip; Space environment -- Periodicals; 551.509992
• DOI: 10.1029/2022SW003236
• Languages: English
• ISSNs: 1542-7390

Abstract

Abstract: The impacts of ionospheric irregularities on precise point positioning (PPP) have been commonly noticed in the field of the ionosphere and the precise application of the Global Navigation Satellite System. But few attentions have been paid to how ionospheric irregularities deteriorate the performance of PPP. Aiming at exploring the mechanism of degradation of PPP solutions during the period of ionospheric irregularities, this paper investigates the impacts of ionospheric irregularities on the performance of kinematic PPP. The experiment uses GPS observation data sampled at the 30‐s interval over China on the days of 2014, 2015, and 2017 covering some active space weather, for example, solar and geomagnetic activities. The results show that the ionospheric irregularities caused increased positioning errors (decimeter‐ to meter‐level), enlarged phase residuals (decimeter‐level), and increased the number of detected cycle slips in PPP processing in low latitude regions of China. By proposing a novel strategy that compares the number of detected cycle slips from 30 s‐sampling interval data and 1s‐sampling interval data at the same station in an "aligned" mode, we present direct evidence of the existence of the falsely detected cycle slips in 30 s‐sampling interval data by the traditional cycle‐slip detection threshold in PPP processing. We reveal that the unnecessary and frequent reinitialization of ambiguity induced by the falsely detected cycle slips is dominantly responsible for the degradation of kinematic PPP solutions during the period of ionospheric irregularities. Our findings pointed out the direction for the improvement of kinematic PPP performance in the environment of ionospheric irregularities. Plain Language Summary: Ionospheric irregularities are electron density irregularities within the ionosphere. Ionospheric irregularity is the main concern in the field of Global Navigation Satellite System (GNSS) due to its impacts on the precise application of GNSS. This paper investigates the impacts of ionospheric irregularities on precise point positioning (PPP) in the region of China. The results indicate that ionospheric irregularities caused decimeter‐level and meter‐level degradation of kinematic PPP in the low‐latitude region of China. Meanwhile, we reveal the mechanism of degradation of kinematic PPP induced by ionospheric irregularities. The falsely detected cycle slips induced by ionospheric irregularities are the dominant reason that causes degradation of kinematic PPP during the period of ionospheric irregularities. Our findings advanced the understanding of the mechanism of the impacts of ionospheric irregularities on kinematic PPP performance. Key Points: Kinematic precise point positioning (PPP) performances in the multi‐event condition of ionospheric irregularities over China are evaluated The ionospheric irregularities caused increased cycle slips and degraded PPP solutions in the south of China from sunset to midnight Extensive misjudged cycle slips are dominantly responsible for the degradation of PPP solution during the period of irregularities