Real-Time Onboard Processing and Monitoring of Ionospheric Scintillation and TEC Low-Cost GNSS-Based Monitors – ScintPi

Ionospheric scintillation monitoring efforts are often limited by the relatively high cost of commercial instrumentation. To address this, Rodrigues and Moraes (2019) and Gomez Socola and Rodrigues (2022) have developed a series of inexpensive ionospheric scintillation and Total Electron Content (TEC) monitors known as ScintPi. ScintPi was developed by combining single-board computers (Raspberry Pi) and Commercial Off-the-Shelf (COTS) Global Navigation Satellite System (GNSS) receivers. Though not intended to replace commercial scintillation monitors, ScintPi systems have proven effective for a variety of ionospheric investigations (e.g., Sousasantos et al., 2023; Gomez Socola et al., 2025; Wright et al., 2025).

While ScintPi has significantly contributed to lowering the costs of scintillation and TEC measurements, we continue to devote efforts related to improving the observations provided by these monitors. Some of these efforts seek to facilitate deployment and operations. In this student-led project, we expand ScintPi observational capabilities by developing onboard computation and real-time visualization of scintillation and TEC products with an interactive online dashboard. Our results build upon the work of previous low-cost real-time scintillation systems (e.g., Freitas et al., 2022; Vankayala et al., 2025) by incorporating multi-GNSS, dual-frequency scintillation measurements and TEC observations.

Scintillation is quantified using the S4 index, calculated from 20 Hz signal intensity measurements directly on the Raspberry Pi using parallel processing in C (POSIX threads). Carrier phase data are down-sampled and used to compute line-of-sight TEC on the front-end dashboard. S4 and phase measurements are stored locally as CSV files and synchronized to an Azure cloud container. Visualization is provided through a Dash web interface that displays the previous 24 hours of activity with five-minute updates, interactive time and satellite selection, and sky-plot visualization.

A prototype of the system has already been field-tested using a ScintPi monitor deployed at the Jicamarca Radio Observatory (11.95° S, 76.87° W; ~0° dip latitude) during conditions of Equatorial Spread F. The real-time ionospheric products (S4 and TEC) show excellent agreement with results obtained through post-processing methods. Onboard processing reduces data sizes from roughly 1 Gigabyte of raw data per day to just a few Megabytes of processed data. This approach enables real-time ionospheric monitoring in areas with limited internet bandwidth. Additionally, unlike static plots, the dashboard has interactive features allowing users to quickly identify scintillation events, inspect specific time intervals, and distinguish between effects such as multipath.

References:

Freitas, M. J. dos S., Moraes, A., Marques, J. C., & Rodrigues, F. (2022). A contribution to real-time space weather monitoring based on scintillation observations and IoT. Advances in Space Research, 70(2), 456–469. https://doi.org/10.1016/j.asr.2022.04.058
Gomez Socola, J., & Rodrigues, F. S. (2022). ScintPi 2.0 and 3.0: Low-cost GNSS-based monitors of ionospheric scintillation and TEC. Earth, Planets and Space, 74(1), 185.
Gomez Socola, J., et al. (2025). ScintPi measurements of low-latitude ionospheric irregularity drifts using spaced-receiver technique and SBAS signals. Atmos. Meas. Tech., 18, 909–919.
Rodrigues, F. S., & Moraes, A. O. (2019). ScintPi: A Low-Cost, Easy-to-Build GPS Ionospheric Scintillation Monitor for DASI Studies of Space Weather, Education, and Citizen Science Initiatives. Earth and Space Science, 6, 1547–1560. https://doi.org/10.1029/2019EA000588
Sousasantos, J., et al. (2023). Severe L-band scintillation from an extreme equatorial plasma bubble: joint ground-based and GOLD observations. Earth, Planets and Space, 75, 41.
Wright, I. G., Gomez Socola, J. and F. S. Rodrigues (2025), Investigating the orientation of low-latitude amplitude fade patterns using a local array of GNSS-based scintillation monitors, URSI Radio Science Letters, 7, https://doi.org/10.46620/25-0021.
Vankayala, H. V., A. Mahadevan, S. S. Kongani, A. S. Reddy and V. R. Devanaboyina, "IoT-Enabled GNSS-based System for Real-Time Ionospheric Scintillation Monitoring," 2025 5th International Conference on Pervasive Computing and Social Networking (ICPCSN), Salem, India, 2025, pp. 935-939,

Acknowledgments:

This work was supported by NSF (AGS- 2432609) and by an NSF GRFP fellowship. We would like to thank the Jicamarca Radio Observatory for hosting the ScintPi unit used in this study.