Ionospheric scintillation intensity fading characteristics and GPS receiver tracking performance at low latitudes

Abstract

Ionospheric scintillation refers to rapid fluctuations in signal amplitude/phase when radio signals propagate through irregularities in the ionosphere. The occurrence of ionospheric scintillation can severely degrade the Global Navigation Satellite System (GNSS) receiver tracking loop performance, with consequential effects on positioning. Under strong scintillation conditions, receivers can even lose lock on satellites, which poses serious threats to safety-critical GNSS applications and precise positioning. The characteristics of intensity fading on Global Positioning System (GPS) L1 C/A signals during the peak of the last solar cycle at the low latitude station of Presidente Prudente (Lat. 22.12°S, Long. 51.41°W, Magnetic Lat. 12.74°S) are investigated. The results show that the occurrence of scintillation at this station is extremely frequent. An analysis of the fading events revealed an inverse relationship between fading depth and duration. Mathematical models are built to investigate and explain the statistical relationship between intensity fading and the commonly used amplitude scintillation index S4. Then the GPS receiver tracking loop performance is studied in relation to fading. A conclusion can be drawn that both fading depth and duration can affect the tracking loop performance, but the tracking error variance is more strongly related to fading speed, defined as the ratio of fading depth to fading duration. The proposed study is of great significance for better understanding the ionospheric scintillation intensity fading characteristics at low latitudes. It can also contribute to the research on the effects of scintillation on GNSS as well as support the design and development of scintillation robust GNSS receivers.

Signal‐In‐Space Performance Under Multiconstellation Environment From an Indian Low Latitude Station

“…Guo et al. (2019) have studied the fading of GPS signal intensity during the maxima of present solar cycle from Presidente Prudente (22.12°S, 51.41°W; geographic) in the Brazilian longitude sector. Their analysis also focused on the effects of signal intensity fading on receiver tracking loop performance.…”

Climatology of Ionospheric Amplitude Scintillation on GNSS Signals at South American Sector During Solar Cycle 24

“…The amplitude scintillation index (S4) is the standard deviation of the signal intensity normalized to the intensity averaged over 60s (Fremouw et al, 1978;Guo et al, 2019) and is given by the Eq. (1).…”

“…Several works have investigated the ionospheric scintillation at the SA sector at some periods of solar cycle 24, which has just ended (e.g., De Rezende et al, 2010;Sreeja et al, 2011;Bougard et al, 2013;Alfonsi et al, 2013;Spogli et al, 2013aSpogli et al, , 2013bCesaroni et al, 2015, Khadka et al, 2016Muella et al, 2017;Correia et al, 2018;Guo et al, 2019;De Paula et al, 2019;Oliveira et al, 2020). Some of these works are worthwhile to highlight.…”

Research on Time-Correlated Errors Using Allan Variance in a Kalman Filter Applicable to Vector-Tracking-Based GNSS Software-Defined Receiver for Autonomous Ground Vehicle Navigation

“…Many difficulties will be encountered by the GNSS signal through its transmission in the atmosphere. It should be noted that the atmospheric noise not only reduces the signals from the GNSS satellites [32][33][34], but also the SAR signals whose performances may be largely reduced when they pass through the ionospheric and tropospheric layers and influenced by the turbulent atmosphere [29,[35][36][37]. The ionospheric modelling is considerably a tricky issue towards the orbital satellite signal processing, and the signal power would be dramatically attenuated by the unintentional turbulence.…”