Assessment of GPS Multifrequency Signal Characteristics During Periods of Ionospheric Scintillations from an Anomaly Crest Location

Abstract

Multifrequency GPS transmissions have provided the opportunity for testing the applicability of the principle of frequency diversity for scintillation mitigation. Published results addressing this issue with quantified estimates are not available in literature, at least from the anomaly crest location of the Indian longitude sector. Multifrequency scattering within the same L band is often the attributed cause behind simultaneous decorrelated signal fluctuations. The present paper aims to provide proportion of time during scintillation patches that decorrelations are found across GPS L1, L2, and L5 frequencies associated with high S4, corresponding high values of scattering coefficients, and large receiver position deviations thereby seriously compromising the performance of satellite‐based navigation system. Results from the anomaly crest station at Calcutta indicate maximum 40% of scintillation time during February–April 2014 and 33% during August–October 2014 that the signals are decorrelated. It is important to note that it is only during these time intervals that the principle of frequency diversity could be applied for scintillation mitigation.

Interfrequency Performance Characterizations of GPS During Signal Outages From an Anomaly Crest Location

“…Delay et al () have previously reported the probability distribution of interrupted tracking of GPS L1, L2C, and L5 signals in terms of scintillation‐induced data gap as a function of S 4 from a station near Brazil, thereby suggesting less robustness of L2C and L5 compared to L1. Decorrelation of GPS triple‐frequency signals, in terms of S 4 and C/N O , during periods of ionospheric scintillations, have been studied by Goswami et al () from Calcutta. Carrano et al () have also emphasized the use of frequency diversity to mitigate the effects of scintillation.…”

“…Vilà‐Valls et al () have presented a new model‐based method to achieve a solution toward mitigation challenges posed by scintillation‐corrupted measurements. Suggested techniques for improvement of satellite signal reception capability may apply the principles of spatial diversity of different satellite constellations (Paul et al, ), frequency diversity between different frequencies of GNSS satellite links (Goswami et al, ) and interoperability between different satellite‐based navigation systems (Goswami et al, ).…”

VHF Scintillation and Drift Studied Using Spaced Receivers in Southern Taiwan

“…• Statistical characteristics of VHF scintillation and drift have been examined for quiet/disturbed periods during 2015-2017 over China sea • Seasonal asymmetry in the occurrence of scintillation was observed in 2015-2016 but no such asymmetry was apparent in 2017 (low solar) • Disturbed period irregularity drift during moderate geomagnetic storm of 08 September 2017 indicated >200% deviation w.r.t. quiet period important constituent of space research aimed at improving the reliability and integrity of the satellite-based navigation (e.g., Goswami et al, 2017;Sridharan et al, 2015). Owing to the increasing dependence of the mankind on the satellite-based navigation, ionospheric irregularities continue to be extensively studied even after several decades of extensive research on this topic.…”

“…They have achieved remarkable successes in their efforts including its real‐time assessment; however, an operational grade model to forecast the day‐to‐day variability in ionospheric scintillation still requires additional investigations to better understand the generation mechanism of intermediate‐scale irregularities. Thus, investigations to understand the background conditions under which these ionospheric irregularities are generated, remains an important constituent of space research aimed at improving the reliability and integrity of the satellite‐based navigation (e.g., Goswami et al, ; Paul & Paul, ; Sridharan et al, ). Owing to the increasing dependence of the mankind on the satellite‐based navigation, ionospheric irregularities continue to be extensively studied even after several decades of extensive research on this topic.…”

Study of Relative Performance of Different Navigational Satellite Constellations Under Adverse Ionospheric Conditions

“…Global Navigation Satellite System (GNSS) provides collectively worldwide positioning, navigation, and timing determination capability using one or more satellite constellations. The reception of multiconstellation satellite signal can enhance the performance of satellite‐based navigation system under conditions of intense ionospheric scintillations as experienced during equinoctial months of high sunspot number years at equatorial locations through application of the principles of spatial diversity (Paul et al, ), frequency diversity (Goswami et al, ), and interoperability. Presently, GPS, GLONASS, GALILEO, and Beidou/COMPASS are the operational GNSS.…”