Bibliography

Creating a Database to Identify High-Latitude Scintillation Signatures With Unsupervised Machine Learning

In high latitudes, Global Navigation Satellite System (GNSS) signals experience scintillation due to moving irregularity structures in the ionosphere. These develop as a result of different physical mechanisms, which are as yet principally described on an elementary level for certain storm cases and events. Since there are years of GNSS data available from stations around the globe, we are investigating an unsupervised Machine Learning approach to extract a large variety of groups of scintillation events with similar features. We create a database containing high-rate scintillation events from two geomagnetic storm cases and several stations in the high-latitude region of the Northern hemisphere. By clustering high-rate signatures in signal phase and power according to their major signal characteristics with an agglomerative hierarchical clustering, it is possible to extract different groups of similar types of scintillation signatures. As a result of this study, the database of scintillation signatures in various locations in the auroral oval and polar cap evolves and will be further expanded beyond the storm cases studied in this paper. These can then be linked to the geomagnetic conditions and dynamics in the ionosphere through additional datasets from other instruments, therefore potentially helping us to get a further insight into the ionospheric irregularity physics.

Bals, Anna-Marie; Thakrar, Chintan; Deshpande, Kshitija;

Published by: IEEE Journal of Radio Frequency Identification      Published on:

YEAR: 2022     DOI: 10.1109/JRFID.2022.3163913

Databases; Feature extraction; Fluctuations; global navigation satellite system; GNSS data noise elimination; GNSS scintillation; Indexes; Instruments; ionospheric scintillation event detection; Radiofrequency identification; unsupervised machine learning

The distribution characteristics of GPS cycle slip over the China mainland and adjacent region during the declining solar activity (2015--2018) period of solar cycle 24

The Global Positioning System (GPS) cycle slip has a marked impact on the application of communication and navigation systems and therefore is one of the main concerns of the user and designer of terminal systems. In this study, we analyzed the temporal and spatial characteristics of cycle slip events using the GPS data detected from 260 observations in the China sector during the period of the year 2015–2018. The results show that the temporal variations of cycle slips are dependent on the local time, seasons, and solar activity. It occurs from 20:00 LT to midnight and more frequently in the equinox months, especially in solar maximum years. The spatial distribution occurs mainly at southern sector below 25°N, which should be associated with the solar condition and ionospheric irregularities in the equatorial region, and the case analyses reveal that the variation of cycle slips has a similar tendency with the ionospheric scintillation monitored at low-latitude station Guangzhou explaining this relationship. Our results reflect the performance of the GPS signals monitored in the China area during the declining period of solar activity to some degree.

Geng, Wei; Huang, Wengeng; Liu, Guoqi; Liu, Siqing; Luo, Binxian; Chen, Yanhong;

Published by: Radio Science      Published on: may

YEAR: 2021     DOI: 10.1029/2020RS007196

Monitoring; Delays; Global positioning system; Indexes; Receivers; Satellite broadcasting; Signal to noise ratio