Better thresholds and weights to improve GNSS PPP under ionospheric scintillation activity at low latitudes

GPS Solutions ◽  
2019 ◽  
Vol 24 (1) ◽  
Author(s):  
Xiaomin Luo ◽  
Shengfeng Gu ◽  
Yidong Lou ◽  
Biyan Chen ◽  
Weiwei Song
2018 ◽  
Vol 8 ◽  
pp. A51 ◽  
Author(s):  
Sreeja Vadakke Veettil ◽  
Marcio Aquino ◽  
Luca Spogli ◽  
Claudio Cesaroni

Ionospheric scintillation can seriously impair the Global Navigation Satellite Systems (GNSS) receiver signal tracking performance, thus affecting the required levels of availability, accuracy and integrity of positioning that supports modern day GNSS based applications. We present results from the research work carried out under the Horizon 2020 European Commission (EC) funded Ionospheric Prediction Service (IPS) project. The statistical models developed to estimate the standard deviation of the receiver Phase Locked Loop (PLL) tracking jitter on the Global Positioning System (GPS) L1 frequency as a function of scintillation levels are presented. The models were developed following the statistical approach of generalized linear modelling on data recorded by networks in operation at high and low latitudes during the years of 2012–2015. The developed models were validated using data from different stations over varying latitudes, which yielded promising results. In the case of mid-latitudes, as the occurrence of strong scintillation is absent, an attempt to develop a dedicated model proved fruitless and, therefore, the models developed for the high and low latitudes were tested for two mid-latitude stations. The developed statistical models can be used to generate receiver tracking jitter maps over a region, providing users with the expected tracking conditions. The approach followed for the development of these models for the GPS L1 frequency can be used as a blueprint for the development of similar models for other GNSS frequencies, which will be the subject of follow on research.


Author(s):  
Juliana G. Damaceno ◽  
Claudio Cesaroni ◽  
Luca Spogli ◽  
Marcin Grzesiak ◽  
Giorgiana De Franceschi ◽  
...  

Author(s):  
Bruno J. Affonso ◽  
Caio C. Marques ◽  
Andre L. A. Silva ◽  
Jonas Sousasantos ◽  
Andre R. F. Martinon ◽  
...  

Author(s):  
Kutubuddin Ansari ◽  
Tae-Suk Bae ◽  
Punyawi Jamjareegulgarn ◽  
Shakera Khan ◽  
Soo-Hyeon Lim

The ionospheric scintillation is a rapid phase and amplitude fluctuation of satellite signals due to the small-scale irregularity of electron density in the ionosphere. The characterization of the scintillation index in a proper way is a crucial aspect of the Global Positioning System (GPS) satellite signals for the purpose of space-based navigation, satellite communication, space weather as well as earth observation applications. In the current study, we analyzed the ionospheric scintillation index during the year of 2018 to 2019 over the Nepal region which locates itself almost being sandwiched between India and China and in the vicinity of low latitudes. The characteristic variations of scintillation occurrence are studied during the several geomagnetic storm and quiet days. The results show that the S4 indexes are varying from the 0.05 to 0.45 during the whole year. The S4 indexes behave higher variations during the whole day in the starting of the year and start to decrease at end of the day as well as at the ending months of the year 2019. The S4 values become completely less during the sunset time, while they have higher values during the sunrise. Especially, the S4 index during the storm days are larger than during the quiet days. It is worthy to note that the variations of S4 index studied in this current study do not follow the sunset property during the year of 2019. Consequently, the causes should be discovered and discussed additionally in the next research paper.


Author(s):  
Kai Guo ◽  
Marcio Aquino ◽  
Sreeja Vadakke Veettil ◽  
Zhizhao Liu ◽  
Wu Chen ◽  
...  

2020 ◽  
Vol 94 (2) ◽  
Author(s):  
Sreeja Vadakke Veettil ◽  
Marcio Aquino ◽  
Haroldo Antonio Marques ◽  
Alison Moraes

2020 ◽  
Vol 12 (15) ◽  
pp. 2373
Author(s):  
Dong L. Wu

Ionospheric scintillation can significantly degrade the performance and the usability of space-based communication and navigation signals. Characterization and prediction of ionospheric scintillation can be made from the Global Navigation Satellite System (GNSS) radio occultation (RO) technique using the measurement from a deep slant path where the RO tangent height (ht) is far below the ionospheric sources. In this study, the L–band S4 from the RO measurements at ht = 30 km is used to infer the amplitude scintillation on the ground. The analysis of global RO data at ht = 30 km shows that sporadic–E (Es), equatorial plasma bubbles (EPBs), and equatorial spread–F (ESF) produce most of the significant S4 enhancements, although the polar S4 is generally weak. The enhanced S4 is a strong function of local time and magnetic dip angle. The Es–induced daytime S4 tends to have a negative correlation with the solar cycle at low latitudes but a positive correlation at high latitudes. The nighttime S4 is dominated by a strong semiannual variation at low latitudes.


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